A matrix compositor was a component of a starship's warp core. The warp core matrix compositor of the USS Malinche became fused after being attacked by a booby-trapped Cardassian freighter and three Maquis raiders in 2373, leaving the ship adrift in space. Captain Sisko beamed a damage control team to the Malinche with twelve micro-power relays to assist Captain Sanders with repairs. (DS9: "For the Uniform") This may have been shorthand for a theta-matrix compositor.