crenation

from The American Heritage® Dictionary of the English Language, 5th Edition.

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

from The Century Dictionary.

• noun Same as crenature.

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

• noun (Bot.) A rounded tooth on the edge of a leaf.
• noun The condition of being crenate.

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

• noun 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.
• noun botany A rounded tooth on the edge of a leaf.
• noun The condition of being crenate.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun 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.)