1690s, Modern Latin, from Greek thrombos "lump, piece, clot of blood, curd of milk," a word of uncertain etymology.
"weathercock," late 14c., from Old English fana, fona "flag, banner," from Proto-Germanic *fanan- (source also of Old Frisian fana, Gothic fana "piece of cloth," Old High German fano, German Fahne "flag, standard"); possibly cognate with Latin pannus "piece of cloth" (see pane).
"flat stone for paving," c. 1600, ultimately from Old Norse flaga "stone slab," from Proto-Germanic *flago- (from extended form of PIE root *plak- (1) "to be flat"). Earlier in English as "piece cut from turf or sod" (mid-15c.), from Old Norse flag "spot where a piece of turf has been cut out," from flaga.