sub·branch I. \ˈ ̷ ̷+ˌ-\intransitive verb Etymology:sub- + branch (v.) : to divide into subbranches II. noun Etymology:sub- + branch (n.) 1.: a branch of a branch < complex organizations that ramify into branches and subbranches > 2.: a branch (as of a business firm) that is of secondary importance and usually less complete in function or service than a main branch