What is "areolation"

Areolation \A`re*o*la"tion\, n.

1. Division into areol[ae].
   --Dana.

2. Any small space, bounded by some part different in color or structure, as the spaces bounded by the nervures of the wings of insects, or those by the veins of leaves; an areola.

n. An areola, or a similar form of a space surrounded by something of a different colour.