a. Min. [f. TRAP sb.5 + -OID.] Resembling or allied to trap-rock.
1842. in Phillips, Man. Geol. (1855), 250. Upon this lies an often trappoid or magnesian conglomerate.
1854. Murchison, Siluria, xiii. 334. A reaggregated trappoid breccia.
1889. Nature, 12 Dec., 140/2. In saucer-like hollows in the solid, tough, trappoid rocks.
