"small piece," late 14c., from Old Norse skrap "scraps, trifles," from skrapa "to scrape, scratch, cut" (see scrape (v.)). Meaning "remains of metal produced after rolling or casting" is from 1790. Scrap iron first recorded 1794.
"fight," 1846, possibly a variant of scrape (n.1) on the notion of "an abrasive encounter." Weekley and OED suggest obsolete colloquial scrap "scheme, villainy, vile intention" (1670s).
"to make into scrap," 1883 (of old locomotives), from scrap (n.1). Related: Scrapped; scrapping.
"to fight, brawl, box," 1867, colloquial, from scrap (n.2). Related: Scrapped; scrapping.
she jotted it on a scrap of paper
there was not a scrap left
the unhappy couple got into a terrible scrap
scrap your old computer
These two fellows are always scrapping over something
scrap the old airplane and sell the parts