In mathematics, to assign a hard value to a potentially influencing variable in order to examine the resulting correlation between two or more other variables. A noun or pronoun can be used between "partial" and "out." Instead of performing a multivariate regression, you can instead partial out each variable individually, examining one by one how each remaining variable affects the values of the others.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.