tag [LME] When first recorded, this word referred to a narrow hanging section of a skirt slashed as a decorative feature. It is of unknown origin but may be related to Late Middle English dag, which had much the same meaning and may be a form of dagger [LME], although this too is of obscure origin. Use of tag for a label indicating ownership began in US English in the mid 19th century. Tab [LME] may be related. It originally described a small flap or strip and is yet again of unknown origin. In American English in the late 19th century it developed the sense ‘an account, bill’, reflected in the idiom of the same date keep tabs on meaning ‘keep a regular check on’ someone.