stepmother (n.) Look up stepmother at Dictionary.com
also step-mother, Old English steopmodor; see step- + mother (n.1). Associated with parsimony and cruelty at least since Middle English.
Is Moder was ded, his fader nam an oþur wijf. ... seint Edward heo louede luyte, for stepmoder is selde guod. ["South English Legendary," c.1300]