old-fashioned slang Condensed milk stored in a tin can. It's pretty hard to get fresh food this far north, so you'll have to use tin cow for your coffee.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
n. canned milk. This tin cow is okay in coffee or something, but you can’t drink it.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.