Port as in to carry/wear is the noun, whereas porte is the corresponding verb. Porte-manteau is the logical form for the combined noun/adjective (as in carry-al

Port as in to carry/wear is the noun, whereas porte is the corresponding verb. Porte-manteau is the logical form for the combined noun/adjective (as in carry-all, see-all). In English the common form for combining meanings is e.g. goal-keeper which in French translates as gardien de but ; porte-manteau is one of the classic cases where it's shortened to verb-noun. (For gardien de but it would be garde-but, which is weird, I guess it sounds like garde-manger.) Port-manteau just wouldn't sound right.