Basic Uniform Commercial Code
"[C]ommingled goods" means goods that are physically united with other goods in such a manner that their identity is lost in a product or mass.
I.e., things like corn or oil that's just mixed in with a lot of other similar goods.
All perfected security interests have equal priority in commingled goods. If there are multiple perfected secured parties, they are perfected in proportion to the value of each's collateral that became commingled goods. UCC § 9-336(f)(2).