\Chlo"ro*plast\, n. [Pref. chloro- + Gr. ? to mold,
form.] (Biol.)
A plastid containing chlorophyll, developed only in cells
exposed to the light. Chloroplasts are minute flattened
granules, usually occurring in great numbers in the cytoplasm
near the cell wall, and consist of a colorless ground
substance saturated with chlorophyll pigments. Under light of
varying intensity they exhibit phototactic movements. In
animals chloroplasts occur only in certain low forms.