Meaning of FLAG in English

n. & v.

n. (also flagstone) 1 a flat usu. rectangular stone slab used for paving. 2 (in pl.) a pavement made of these.

v.tr. (flagged, flagging) pave with flags.

[ ME, = sod: cf. Icel. flag spot from which a sod has been cut out, ON flaga slab of stone, and FLAKE(1) ]

Concise Oxford English dictionary.      Краткий оксфордский словарь английского языка.