Appealable Collateral Order Law and Legal Definition
An appealable "collateral order" is defined as “an order that conclusively determines an important issue that is separate from the merits in such a way as to render a district court's resolution of that issue un-reviewable on appeal from a final judgment.” [McKee v. Lang, 2010 U.S. App. LEXIS 18516 (5th Cir. Tex. Sept. 1, 2010)].