stepmother

äitipuoli The wife of one's biological father, other than one's biological mother.
puhekieltä A viola, especially Viola tricolor, heartsease.
1974, Thomas Teal, translating Tove Jansson, The Summer Book, Sort Of Books 2003, p. 115:

The second came up about ten days later in the lee of the channel marker, and it was called stepmother, or love-in-idelness.