A pouch was a soft-sided sack in which objects of value were kept.
In 2268, Mister Lurry handed James T. Kirk a pouch containing a sample of quadrotriticale to examine. Later, Kirk passed it on to Pavel Chekov, who left it on the Deep Space Station K-7's bar counter, where its contents were promptly consumed by a tribble. (TOS: "The Trouble with Tribbles")