I. ˌsurrogate ˈmother BrE AmE ( also surrogate ) noun [countable]
a woman who has a baby for another woman who cannot have one, and then gives her the baby after it is born
II. sur ‧ ro ‧ gate 1 /ˈsʌrəɡeɪt, -ɡət $ ˈsɜːr-/ BrE AmE adjective [only before noun]
a surrogate person or thing is one that takes the place of someone or something else:
William was acting as a surrogate father for his brother’s son.
III. surrogate 2 BrE AmE noun [countable]
[ Date: 1500-1600 ; Language: Latin ; Origin: past participle of surrogare 'to ask in place of another' , from sub- ( ⇨ ↑ sub- ) + rogare 'to ask' ]
1 . a person or thing that takes the place of someone or something else
surrogate for
Bright-light therapy is used as a surrogate for sunshine.
2 . a surrogate mother