leucoplast

from The Century Dictionary.

• noun Same as amyloplast.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Bot.) One of certain very minute whitish or colorless granules occurring in the protoplasm of plants and supposed to be the nuclei around which starch granules will form.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun biology An organelle found in certain plant cells, a non-pigmented category of plastid with various biosynthetic functions.