1650s, "to hack, chop into small pieces," from French hacher "chop up," from Old French hache "ax" (see hatchet). Hash browns is short for hash browned potatoes (1917), with the -ed omitted, as in mash potatoes. The hash marks on a football field were so called 1960s, from similarity to hash marks, armed forces slang for "service stripes on the sleeve of a military uniform" (1909), which supposedly were called that because they mark the number of years one has had free food (hash, n.1) from the Army; but perhaps there is a connection with the noun form of hatch, v.2.