<p><strong>noun</strong></p><ul><li>A close or intimate companion: boyhood chums.</li><li>A roommate, as at college.</li></ul><p><strong>verb</strong></p><ul><li>(used without object) chummed, chumming.</li><li>To associate closely.</li><li>(Older Use) To share a room or rooms with another, especially in a dormitory at a college or prep school.</li></ul>