Two meanings of -bound
-bound forms adjectives with two distinct senses, both from the past participle of "to bind" (to tie, to obligate): Sense 1: CONFINED BY / TRAPPED IN: snowbound (trapped by snow), fogbound (trapped by fog), housebound (unable to leave the house), deskbound (confined to a desk), earthbound (unable to leave earth). Sense 2: HEADED TOWARD: inbound (heading toward a destination), outbound (heading away), homebound (heading home), northbound (heading north), southbound (heading south).