scrap (n.1) Look up scrap at Dictionary.com
"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.
scrap (n.2) Look up scrap at Dictionary.com
"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).
scrap (v.2) Look up scrap at Dictionary.com
"to fight, brawl, box," 1867, colloquial, from scrap (n.2). Related: Scrapped; scrapping.
scrap (v.1) Look up scrap at Dictionary.com
"to make into scrap," 1883 (of old locomotives), from scrap (n.1). Related: Scrapped; scrapping.