n. The act or result of surrogating; replacement, substitution
the GNU version of the Collaborative International Dictionary of English
n. The act of substituting one person in the place of another.
The Century Dictionary and Cyclopedia
n. Same as subrogation.
Word Usage
"UPDATE: Based on questioning in the comments and a little Googling, I'm convinced "surrugation" is not some technical term or some Canadian word, but a misspelling of "surrogation.""