Definition of "stepmother"

stepmother

/ˈstɛpmʌðə/

noun
plural stepmothers
1. The wife of one's biological father, other than one's biological mother.
2. (botany, rare) A viola, especially Viola tricolor, heartsease.
  Quotations
  The second came up about ten days later in the lee of the channel marker, and it was called stepmother, or love-in-idelness.
  1974, Tove Jansson, translated by Thomas Teal, The Summer Book, Sort Of Books, published 2003, page 115