areolation

from The Century Dictionary.

• noun The state of being areolate in character, or of having an areola, or of division into areolæ; the arrangement and form of areolæ as in the leaves of mosses.
• noun 2. A set of areolæ taken together as making something areolate.

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

• noun Division into areolæ.
• noun 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.

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

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