tag (Noun) — A label written or printed on paper, cardboard, or plastic that is attached to something to indicate its owner, nature, price, etc..
tag (Noun) — A label associated with something for the purpose of identification. ex. "semantic tags were attached in order to identify different meanings of the word"
tag (Noun) — A small piece of cloth or paper.
tag (Noun) — A game in which one child chases the others; the one who is caught becomes the next chaser.
tag (Noun) — (sports) the act of touching a player in a game (which changes their status in the game).
tag (Noun) — (computing) an identifier associated with a piece of data.
tag (Verb) — Attach a tag or label to. ex. "tag these bottles"
tag (Verb) — (baseball) touch a player while he is holding the ball.
tag (Verb) — Provide with a name or nickname.
tag (Verb) — Go after with the intent to catch. ex. "The policeman tagged the mugger down the alley"
tag (Verb) — (poetry) supply (blank verse or prose) with rhymes.