n. 1. A strip of leather, paper, metal, or plastic attached to something or hung from a wearer's neck to identify, classify, or label: sale tags on all coats and dresses.
2. The plastic or metal tip at the end of a shoelace.
3. The contrastingly colored tip of an animal's tail.
4. a. A dirty, matted lock of wool.
b. A loose lock of hair.
5. A rag; a tatter.
6. A small, loose fragment: I heard only tags and snippets of what was being said.
7. An ornamental flourish, especially at the end of a signature.
8. A designation or epithet, especially an unwelcome one: He did not take kindly to the tag of pauper.
9. a. A brief quotation used in a discourse to give it an air of erudition or authority: Shakespearean tags.
b. A cliché, saw, or similar short, conventional idea used to embellish a discourse: These tags of wit and wisdom bore me.
c. The refrain or last lines of a song or poem.
d. The closing lines of a speech in a play; a cue.
10. Computers a. A label assigned to identify data in memory.
b. A sequence of characters in a markup language used to provide information, such as formatting specifications, about a document.
c. A metatag.
11. Anatomy A small outgrowth or polyp: a skin tag.
12. Slang A piece of graffiti featuring text, especially the author's name, rather than a picture: “Instead of a cursive linear tag, Super Kool painted his name along the exterior of a subway car in huge block pink and yellow letters” (Eric Scigliano).
v. tr. 1. To label, identify, or recognize with a tag or other identifier: I tagged him as a loser.
2. To put a ticket on (a motor vehicle) for a traffic or parking violation.
3. To add as an appendage to: tagged an extra paragraph on the letter.
4. To follow closely: Excited children tagged the circus parade to the end of its route.
5. To cut the tags from (sheep).
6. To add a taggant to: explosives that were tagged with coded microscopic bits of plastic.
7. To incorporate into (a compound) a more readily detected substance whereby the compound can be detected and its metabolic or chemical history followed.
8. Slang To mark or vandalize (a surface) with a graffiti tag: tagged the subway walls.
[Middle English, dangling piece of cloth on a garment, possibly of Scandinavian origin; akin to Swedish tagg, prickle, thorn.]