Google Dictionary:
tag1
taɡ/Submit noun
1. a label attached to someone or something for the purpose of identification or to give other information. "he gave his pet a collar with a metal name tag" synonyms: label, ticket, badge, mark, marker, tab, tally, sticker, docket, stub, chit, chitty, counterfoil, flag, stamp "a price tag"
2. a small piece or part that is attached to a main body.
verb
1. attach a label to. "mothers suspected that their babies had been wrongly tagged during an alarm at the hospital" synonyms: label, attach tags to, put a label on, mark, ticket, earmark, identify, docket, flag, indicate "the bottles were tagged with colour-coded labels"
2. add to something, especially as an afterthought or with no real connection. "she meant to tag her question on at the end of her remarks" synonyms: add, tack, join; attach, append, affix, annex "their heads were so large that the rest of their bodies seemed tagged on as an afterthought"
Tag : Merriam-Webster Dictionary : Link
Tag : Oxford Dictionary : Link