lengthwise I. \ˈ ̷ ̷ˌ ̷ ̷\adverb Etymology:length + -wise : in the direction of the length : longitudinally < opened his newspaper, folded it lengthwise — Nathaniel Benchley > II. adjective : moving, placed, or directed on or toward the long axis < tiers of planks had been fashioned into lengthwise seats — Agnes M. Cleaveland >