The Collaborative International Dictionary of English v.0.48:

Moneywort \Mon"ey*wort`\, n. (Bot.)
   A trailing plant (Lysimachia Nummularia), with rounded
   opposite leaves and solitary yellow flowers in their axils.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Lysimachia nummularia
    n 1: a loosestrife vine [syn: moneywort, creeping Jenny,
         creeping Charlie, Lysimachia nummularia]