What is "crenulation"

Crenulation \Cren`u*la"tion\ (-l?"sh?n), n.

1. A minute crenation.

2. The state of being minutely scalloped.

n. 1 A minute crenation. 2 The state of being minutely scalloped.

In a geological context, crenulation or crenulation cleavage is a fabric formed in metamorphic rocks such as phyllite, schist and some gneiss by two or more stress directions causing the formation of the superimposed foliations.