"strip of wood (especially used to fasten canvas over ships' hatches)," 1650s, anglicized variant of baton "a stick, a staff" (see baton). Nautical use attested from 1769.
"to improve; to fatten," 1590s, probably representing an English dialectal survival of Old Norse batna "improve" (cf. Old English batian, Old Frisian batia, Old High German bazen, Gothic gabatnan "to become better, avail, benefit," Old English bet "better;" cf. also boot (v.)). Related: Battened; battening.
"to furnish with battens," 1775, from batten (n.); phrase batten down recorded from 1823. Related: Battened; battening.