surrogate
🇺🇸
/ˈsɜːrəɡət/
🇬🇧
/ˈsʌrəɡət/
acting as a substitute or replacement
A surrogate mother carries a baby for someone else who cannot have a child.
a person who takes the place of another in a specific role or function
In the experiment, the scientists used a computer as a surrogate for the human brain.