A label is a piece of paper, polymer, cloth, metal, or other material affixed to a container or article, on which is printed a legend, information concerning the product, addresses, etc. Information printed directly on a container or article can also be considered labeling.
Heat activated adhesives: for example, "in-mold labeling" can be part of blow molding containers and employs heat activated adhesives. Hot melt adhesives are also used.
Pressure-sensitive adhesives (also called PSA or self-stick) are applied with light pressure without activation or heat. PSA labels often have release liners which protect the adhesive and assist label handling.
Rivets used to attach information plates to industrial equipment
Shrink wrap for printed shrinkable labels placed over packages and then heated to shrink them
Sewing for clothing, tents, mattresses, industrial sacks, etc.
Pressure-sensitive label adhesives are commonly made from water based acrylic adhesives, with a smaller volume made using solvent based adhesives and hotmelt adhesives. The most common adhesive types are:
Permanent – Typically not designed to be removed without tearing the stock, damaging the surface, or using solvents. The adhesion strength and speed can also be varied. For example, full adhesion can be nearly instant, or the label can be almost removable for a short period with full adhesion developing in minutes or hours (known as respositionable adhesives).
Peelable – Adhesion is fairly strong and will not fall off in normal circumstances, but the label can be removed relatively easily without tearing the base stock or leaving adhesive behind on the old surface. The adhesive is usually strong enough to be applied again elsewhere. This type is frequently known as 'removable'. There are many different types of removable adhesives, some are almost permanent, some are almost 'ultra peelable'.
Ultra-peelable – Designed principally for use on book covers and glass, when removed these adhesives labels do not leave any residue whatsoever. Adhesion is weak and only suitable for light duty applications. Normally these labels have very little adhesion to anything once they've been removed.
Freezer or Frost fix – Most permanent and peelable adhesives have a service temperature limit of -10 degrees Celsius, whereas freezer (otherwise known as frost fix) adhesives have a service temperature -40 degrees Celsius and are suitable for deep freeze use.
High Tack – A type of permanent adhesive that exhibits a high initial grab to the application surfaces, and is commonly used at higher coat weights to enable labels to adhere strongly to difficult, rough or dirty surfaces.
Static Cling – This is not actually an adhesive at all. The material (usually PVA) has a static charge to enable its adhesion to flat, smooth surfaces such as glass. It is not sticky as such and is commonly used for window advertising, window decorations, oil change labels, etc.
The "label stock" is the carrier which is commonly coated on one side with adhesive and usually printed on the other side. Label stocks can be a wide variety of papers, films, fabric, foils, etc.
Litho – one of the most common base stocks
Latex – a litho stock with some added latex allows the label to be much more flexible and form around certain curved objects more easily than standard litho.
Various plastics such as acetate, vinyl, and PET film allow a variety of features, such as greater strength,flexibility[disambiguation needed]transparency, resistance to tearing, etc. They typically require special equipment and printing methods (ultra-violet curing is common) as they do not normally print well with conventional ink. A bumper sticker is usually a vinyl label with a very strong, durable adhesive and lightfast inks. Embossing tape is "printed" by pressing raised elements similar to printing type onto it, which produces raised glyphs that look white due to discoloration of the plastic. A type known as 'Destructible Vinyl' is commonly used for asset labels. It combines a very thin frangible face stock with a very strong high tack adhesive, thus making the label impossible to remove without damaging it. Engraved multi-layer Traffolyte labels are frequently used in industrial situations due to their durability.
Thermal – direct thermal label stock will change color (usually black) when heated. A heating element in the shape of letters or images can be used to create an image on the label. Custom labels can be easily be made on location in this way. A disadvantage is durability, because another heat source can ruin or obscure the image, or it may fade completely over time.
Thermal Transfer for applications that cannot use Thermal (Thermal Direct) label material because of heat source proximity or short label life, a more widely used material is Thermal Transfer Label printer. This material has the advantage of a much longer readable life and does not fade with time or heat. Most major manufacturers of Thermal Printers can be used for either Thermal Transfer (TT) or Thermal (DT) labels. A thermal transfer ribbon will be required to print the labels. The cost of the ribbons + TT labels is similar to that of the DT labels on their own.
Some labels designed on a notebook.
None – labels can be printed directly on adhesive without using a substrate. Labels made in this manner are extremely fragile, however, and have been rendered virtually obsolete by other printing methods such as silk screen.
Thermal Transfer Ribbon Types
Wax is the most popular with some smudge resistance, and is suitable for matte and semi-gloss paper labels.
Wax / Resin is smudge resistant, suitable for semi-gloss paper and some synthetic labels.
Resin is scratch and chemical resistant, suitable for coated synthetic labels.
The stock type will affect the types of ink that will print well on them.
Corona treating or flame treating some plastics makes them more receptive to inks and adhesives by reducing surface tension.
Ink and base stock color choices commonly conform to the Pantone Matching System (PMS) colors. The Pantone system is very dominant in the label printing industry. Additionally specialty inks such as metallic, UV ink, magnetic ink, and more are available. Ink is usually transparent however it can be made opaque. It has been known for certain companies to patent "their own" color. Digital labels use process colors to replicate Pantone solid colors.
Specialized labels 
Piggyback labels are made from combining two layers of adhesive substrate. The bottom layer forms the backing for the top. The label can be applied to any object as normal, the top layer can be a removable label that can be applied elsewhere, which may change the message or marking on the remaining label underneath. Often used on Express mail envelopes.Other applications include price change labels where when being scanned at the till the till assistant can peel back the price-reduction label and scan the original barcode enabling stock flow management. Also, as the retained label is adhesive free it prevents customers from re-applying the cheaper priced labels to premium products.
Laser Labels are generally die cut on 8.5" x 11" sheets(US letter) and a4 size, and come in many different shapes, sizes, and materials. Laser label material is a nonporous stock made to withstand the intense heat of laser printers and copiers. A drawback of laser labels is that the entire sheet needs to be printed before any labels are used; once labels have been removed the sheet cannot be put through the printer again without damaging the printing mechanism.
Inkjet Labels are generally die cut on 8.5" x 11" sheets (US letter) and a4 size, and come in many different shapes, sizes, and materials. Inkjet label material is a porous stock made to accept ink and dye from an inkjet printer. One of the more modern inkjet label material stocks is waterproof printable inkjet material commonly used for soap or shower gel containers.
AntiMicrobial Labels With the growth in hospital acquired infections such as MRSA and E-Coli the use of Antimicrobial labels in infection sensitive areas of hospitals are helping in combating these types of microbes.
Fold-out Labels also known as booklet, multi-page or extended labels, or lablets (combined label + leaflet). Where the pack is not large enough for a single label to carry all the required information, fold-out labels are often preferred to separate leaflets, which can easily be lost. These labels are frequently seen on agricultural chemicals and consumer pharmaceuticals.
Permanent product identification by a label is common. These labels need to be able to bond securely to the surface for its intended life and under in-use conditions. For example a label on an automobile engine needs to be resistant to the heat and oils encountered and to be secure for many years of use.
Removable product labels need to hold until they must be removed. For example, a label on a new refrigerator has installation and usage information: the label needs to be able to be removed cleanly and easily from the unit once installed.
An eco-label is used on consumer products (including foods) to identify products that may be less damaging to the environment and/or to humankind than other related products.
In industrial environments, asset labeling is used to clearly identify assets for maintenance and operational purposes. Such labels are frequently made of engraved Traffolyte or a similar material.
In certain clothing articles, a label or other affixed instructions that report how a product should be refurbished. This type of label is required by the FTC, Federal Trade Commission, for certain clothing items in the United States of America. According to the United States Environmental Protection Agency (EPA), all sales of textiles containing pesticides as an ingredient must be properly labeled according to the United States labeling requirements and must be approved for sale by the EPA. The label has to provide the pesticide registration number, a proper statement of ingredients, as well as the storage and disposal information. The following statement has to appear on the label: "It is a violation of Federal Law to use this product in a manner inconsistent with its labeling”. It is hence essential for suppliers to ensure that pesticide-treated products provide the correct labels and use the language required and approved by the EPA for pesticide treated articles. The import, sale and distribution of mislabeled pesticide-treated products violate federal pesticide regulations and will be subject to fines.
A label including a company name or identification number and a material content list may also be required for certain textile items.
The common textile labels used on garments can be classified into four main groups – Woven labels, Leather labels, PVC/Plastic Labels, and Embroidered Labels. It is one of the primary tools used to establish brand identity.
Packaging often has labels attached to (or integral with) the package. These communicate pricing, barcodes, UPC identification, usage guidance, addresses, advertising, recipes, and so on. They also may be used to help resist or indicate tampering or pilferage. Often high speed label printer applicators are used to apply labels to packages.
Letters and packages need labels to identify the addressee and the sender. Many software packages such as word processor and contact manager programs produce standardized mailing labels from a data set that comply with postal standards. These labels may also include routing barcodes and special handling requirements to expedite delivery.
Pricing gun is tool normally used in departmental stores, grocery and other retail businesses. Pricing guns are used to label store products with a small sticker that indicates the current price of that item. While there are a wide variety of pricing gun manufacturers that offer different styles and features, most pricing guns operate in a similar manner. The gun dispenses labels with adhesive backs, allowing the gun's user to affix labels to merchandise. Periodically label rolls run out and need to be replaced.
Using a pricing gun one can mark retail stock prices quickly. In order to use it, the label gun should be held by the handle with the sticker dispenser pointed towards the object which needs to be priced. The lever tabs on both sides should be held firmly from the upper cover and then the lever tab should be pulled gently.
There are two types of tagging guns, fine fabric and standard guns. Fine fabric guns are used for delicate materials that would otherwise be damaged if a regular gun is used like silk and other delicate clothes, but are also used for every day items as well. Regular guns are normally used in grocery stores.
Labels can aid in recycling and reuse by communicating the material content of the item, instructions for disassembly, recycling directions, etc.
Based on the solid waste hierarchy, the quantity and size of labels should be minimized without reducing necessary functionality. Material content of a label should comply with applicable regulations. Life cycle assessments of the item being labeled and of the label itself are useful to identify and improve possible environmental effects. For example, reuse or recycling are sometimes aided by a label being removable from a surface. If a label remains on an item during recycling, a label should be chosen which does not hinder the recyclability of the item.