The American Heritage® Dictionary of the English Language, 4th Edition
n. Any of several plants, such as a clover or wood sorrel, having compound leaves with three small leaflets, considered the national emblem of Ireland.
n. The trefoil leaf of any small clover, especially Trifolium repens, or such a leaf from a clover-like plant.
n. Any of several small plants, forms of clover, with trefoil leaves, especially Trifolium repens.
the GNU version of the Collaborative International Dictionary of English
n. A trifoliate plant used as a national emblem by the Irish. The legend is that St. Patrick once plucked a leaf of it for use in illustrating the doctrine of the trinity.
The Century Dictionary and Cyclopedia
n. A plant with trifoliate leaves: the national emblem of Ireland.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. Eurasian plant with heart-shaped trifoliate leaves and white purple-veined flowers
n. creeping European clover having white to pink flowers and bright green leaves; naturalized in United States; widely grown for forage
n. clover native to Ireland with yellowish flowers; often considered the true or original shamrock
Word Usage
"Three men were attempting to do the Riverdance in shamrock-shaped slippers."