Definition of foster- in English:

foster-

combining form

  • 1Denoting someone that has a specified family connection through fostering.

    ‘foster-parent’
    ‘foster-child’
    1. 1.1 Involving or concerned with fostering a child.
      ‘foster care’

Origin

Foster-father, foster-mother, foster-child, and foster-brother all date from Old English. Foster-mother has also been used to mean a wet nurse, her husband being foster-father to the child she fed, and a foster-brother or -sister one reared at the same breast.

Pronunciation

foster-

/fɒstə/