Used mostly in Canadian divorce law to refer to relief other than for a divorce, but which typically accompanies a divorce action, such as child custody, spousal or child maintenance or a division of matrimonial property.
Oddly, in the Canadian Divorce Act, the term appears only as a heading, but under which are catalogued support and custody claims.
In Cook v Cook, published at 120 DLR 3d 216 (1981) Justice Goodridge of the Newfoundland Supreme Court said this about "corollary relief" in the context of the federal divorce legislation:
"There are two dominant themes -- consequential and additional. It is obvious that a corollary is something bound by some tie to a principal matter.
"In this case the relief must be consequential or additional to the divorce relief. The legislation creates a nexus between the one and the other.
"This is perhaps better illustrated by the definition of corollary in Webster's New Collegiate Dictionary: (1): an immediate inference from a proved proposition (2)(a): something that naturally follows: result (b): something that incidentally or naturally accompanies or parallels."
In England, in the same context, the word ancillary is preferred.