The Collaborative International Dictionary of English v.0.48:

Petechiae \Pe*tech"i*[ae]\, n. pl.; sing. Petechia. [NL., fr.
   LL. peteccia; cf. F. p['e]t['e]chie, It. petecchia, Sp.
   petequia, Gr. pitta`kion a label, plaster.] (Med.)
   Small crimson, purple, or livid spots, like flea-bites, due
   to extravasation of blood, which appear on the skin in
   malignant fevers, etc.
   [1913 Webster]

WordNet (r) 3.0 (2006):

petechia
    n 1: a minute red or purple spot on the surface of the skin as
         the result of tiny hemorrhages of blood vessels in the skin
         (as in typhoid fever)