A series of small rounded notches or scallops, especially on the edges of leaves or cells.
From Latin 'crena' (notch, scallop) plus the suffix -ation, describing the pattern or process of having a scalloped margin.
Red blood cells actually show 'crenation' when placed in salt water—they shrivel up with a bumpy, scalloped edge, which is why biologists study this in every textbook!
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