tag

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Games A children's game in which one player pursues the others until he or she is able to touch one of them, who then in turn becomes the pursuer.
• noun Baseball The act of tagging a base runner.
• noun Sports The act of tagging a ball carrier in touch football.
• transitive verb To touch (another player) in the game of tag.
• transitive verb Baseball To touch (a base runner) with the ball in order to make a putout.
• transitive verb Sports To touch (a ball carrier) to end a play in touch football.
• noun A strip of leather, paper, metal, or plastic attached to something or hung from a wearer's neck to identify, classify, or label.
• noun The plastic or metal tip at the end of a shoelace.
• noun The contrastingly colored tip of an animal's tail.
• noun A dirty, matted lock of wool.
• noun A loose lock of hair.
• noun A rag; a tatter.
• noun A small, loose fragment.
• noun An ornamental flourish, especially at the end of a signature.
• noun A designation or epithet, especially an unwelcome one.
• noun A brief quotation used in a discourse to give it an air of erudition or authority.
• noun A cliché, saw, or similar short, conventional idea used to embellish a discourse.
• noun The refrain or last lines of a song or poem.
• noun The closing lines of a speech in a play; a cue.
• noun A label assigned to identify data in memory.
• noun A sequence of characters in a markup language used to provide information, such as formatting specifications, about a document.
• noun A metatag.
• noun Slang A piece of graffiti featuring text, especially the author's name, rather than a picture.
• intransitive verb To label, identify, or recognize with a tag or other identifier.
• intransitive verb To put a ticket on (a motor vehicle) for a traffic or parking violation.
• intransitive verb To add as an appendage to.
• intransitive verb To follow closely.
• intransitive verb To cut the tags from (sheep).
• intransitive verb To add a taggant to.
• intransitive verb Slang To mark or vandalize (a surface) with a graffiti tag.
• intransitive verb To follow after; accompany.

from The Century Dictionary.

• noun A children's game in which one player chases the others till he touches or hits (tags) one of them, who then takes his place as tagger.
• noun A point of metal or other hard substance at the end of a cord, string, lace, ribbon, strap, or the like; an aglet.
• noun Hence, any pendant or appendage; a part or piece hanging loosely from the rest, as a flap, string, lock of hair, tail, or other appendage.
• noun Specifically— A matted lock of wool on a sheep; a tag-lock. See tag, transitive verb, 5.
• noun The tail of an animal; also, the tip of the tail.
• noun A strip of leather, parchment, strong paper, or the like, loose at one end, and secured to a box, bag, or parcel, to receive a written address or label.
• noun Anything hanging loosely or raggedly: used especially in contempt, as implying ragged or slovenly dress.
• noun Something added or tacked on to the close of a composition or a performance; an extrinsic or explanatory supplement. In this use the envoy of a poem, the moral of a fable, or the appendix (but not properly the index) to a book is a tag; but the word is used technically of a closing speech or dialogue supplementary to a speech in a play, not necessary to its completeness, and often constituting a direct appeal to the audience for applause.
• noun Collectively, the rabble; the lowest class of people, as closing the line of social rank, and forming as it were a string or tail: most commonly in the phrases tag and rag and rag-tag and bobtail or tag, rag, and bobtail. See ragtag and tag-rag.
• noun In velvet-weaving, a wire used to raise the weft.
• To furnish with a tag of any kind; fix or append a tag or tags to.
• To mark by or on a tag; designate or direct by means of a marked tag.
• To fasten or join on by or as if by the use of tags; tack on, especially in the sense of adding something superfluous or undesirable.
• To follow closely and persistently; dog the steps of: as, a dog tags its master.
• To remove tags from (sheep)—that is, to cut off clotted tags or locks of wool in exposed places, preparatory to the removal of the sheep from winter quarters. See tagging.