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Any of several cytoplasmic organelles, such as chloroplasts, that contain genetic material, have a double membrane, and are often pigmented. Plastids are found in plants, algae, and certain other eukaryotic organisms and have various physiological functions, such as the synthesis and storage of food.
[From Greek plastis, plastid-, feminine of plastēs, molder, from plastos, molded; see plastic.]
plas·tid′i·al (plăs-tĭd′ē-əl) adj.
relating to a plastid