PLASTID
- a structure in plant cells [n PLASTIDS]
- any of various cytoplasmic organelles (as an amyloplast or chloroplast) of photosynthetic cells that serve in many cases as centers of special metabolic activities
- small, double-membraned organelle of plant cells and certain protists, occurring in several varieties, as the chloroplast, and containing ribosomes, prokaryotic DNA, and, often, pigment