crenation

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A rounded projection, as on the margin of a shell.
2. n. The condition or state of being crenate.
3. n. A process resulting from osmosis in which red blood cells, in a hypertonic solution, undergo shrinkage and acquire a notched or scalloped surface.

Century Dictionary and Cyclopedia

1. n. Same as crenature.

Wiktionary

1. n. The contraction of, or formation of abnormal notchings around, the edges of a cell after exposure to a hypertonic solution, due to the loss of water through osmosis, especially noticeable in red blood cells.
2. n. botany A rounded tooth on the edge of a leaf.
3. n. The condition of being crenate.

GNU Webster's 1913

1. n. (Bot.) A rounded tooth on the edge of a leaf.
2. n. The condition of being crenate.

WordNet 3.0

1. n. one of a series of rounded projections (or the notches between them) formed by curves along an edge (as the edge of a leaf or piece of cloth or the margin of a shell or a shriveled red blood cell observed in a hypertonic solution etc.)