sham·rock /ˈʃæmˌrɑk/
 天藍
 Sham·rock n.  Bot. 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.
 Note: ☞ The original plant was probably a kind of wood sorrel (Oxalis Acetocella); but now the name is given to the white clover (Trifolium repens), and the black medic (Medicago lupulina).
 ◄ ►
 shamrock
      n 1: creeping European clover having white to pink flowers and
           bright green leaves; naturalized in United States;
           widely grown for forage [syn: white clover, dutch
           clover, Trifolium repens]
      2: Eurasian plant with heart-shaped trifoliate leaves and white
         pink- or purple-veined flowers [syn: common wood sorrel,
          cuckoo bread, Oxalis acetosella]
      3: clover native to Ireland with yellowish flowers; often
         considered the true or original shamrock [syn: hop clover,
          lesser yellow trefoil, Trifolium dubium]