• WordNet 3.6
    • n lunule the crescent-shaped area at the base of the human fingernail
    • ***
Webster's Revised Unabridged Dictionary
    • Lunule (Chem) A lune. See Lune.
    • Lunule (Zoöl) A small or narrow crescent.
    • Lunule (Zoöl) A special area in front of the beak of many bivalve shells. It sometimes has the shape of a double crescent, but is oftener heart-shaped. See Illust. of Bivalve.
    • Lunule (Anat) Anything crescent-shaped; a crescent-shaped part or mark; a lunula; a lune.
    • ***
Century Dictionary and Cyclopedia
    • n lunule Something in the shape of a little moon or crescent. In conchology, the lunula, a crescentic impression on each valve of many bivalve shells, in front of the umbo, forming with its fellow an oval or somewhat cordate figure; it is conspicuous in the Veneridæ and many related forms.
    • n lunule One of the perforations formed by the union of digitate processes of the test of certain thin forms of echinoids, as Rotula Augusti.
    • ***
Chambers's Twentieth Century Dictionary
    • ns Lunule anything in form like a small crescent
    • ***


Webster's Revised Unabridged Dictionary
F., fr. L. lunula, dim. of luna, moon
Chambers's Twentieth Century Dictionary
L. lunarisluna, the moon—lucēre, to shine.


In literature:

Lunulate: a line, when made up of a series of small lunules.
"Explanation of Terms Used in Entomology" by John. B. Smith
This is a ridiculous attempt, which defies description, except that it is all about lunules.
"A Budget of Paradoxes, Volume I (of II)" by Augustus De Morgan
Legs deep rufous; antennae black; the club beneath and lunule round the eye straw-coloured.
"Zoological Illustrations, Volume I" by William Swainson