the.com/surrogate

means A stand-in who takes on someone else's role or duty — most literally, a person who carries a pregnancy for another person or couple.

from From Latin surrogatus, past participle of surrogare — 'to put in another's place,' built from sub- ('in place of') plus rogare ('to ask, propose,' the same root behind 'interrogate'). It originally traveled through legal and ecclesiastical English for a deputy or substitute appointed to act for someone else — a judge's stand-in, a bishop's proxy — long before it narrowed, in the 20th century, toward its now-dominant sense of a woman carrying a pregnancy on another's behalf.