word-forming element typically representing cross as a noun, adverb (cross-examine), adjective (crossbar), and in many words a confluence of them. "There is no distinct line of division between cross as an adjective and cross as a prefix. As a prefix, it often represents the adv. cross, or the prep. cross, across." [Century Dictionary]
"way of proceeding, manner," Old English wise "way, fashion, custom, habit, manner; condition, state, circumstance," from Proto-Germanic *wison "appearance, form, manner" (see wise (adj.)). Compare Old Saxon wisa, Old Frisian wis, Danish vis, Middle Dutch wise, Dutch wijs, Old High German wisa, German Weise "way, manner." Most common in English now as a word-forming element (as in likewise, clockwise); the adverbial -wise has been used thus since Old English. For sense evolution from "to see" to "way of proceeding," compare cognate Greek eidos "form, shape, kind," also "course of action." Ground sense is "to see/know the way."