As nouns the difference between plastid and apicoplast

is that plastid is (biology) any of various organelles found in the cells of plants and algae, often concerned with photosynthesis while apicoplast is a relict, non-photosynthetic plastid found in most of the apicomplexa , proposed to have evolved via secondary endosymbiosis and surrounded by four membranes within the outermost part of the endomembrane system.