late 13c., from Old French coton (12c.), ultimately (via Provençal, Italian, or Old Spanish) from Arabic qutn, a word perhaps of Egyptian origin. Philip Miller of the Chelsea Physic Garden sent the first cotton seeds to American colony of Georgia in 1732. Also ultimately from the Arabic word, Dutch katoen, German Kattun, Provençal coton, Italian cotone, Spanish algodon, Portuguese algodão. Cotton gin is recorded from 1794 (see gin (n.2)).
"to get on with" someone (usually with to), 1560s, perhaps from Welsh cytuno "consent, agree." But perhaps also a metaphor from cloth finishing and thus from cotton (n.). Related: Cottoned; cottoning.