To confine in a pound or pen; to confine; to take possession of.
- Nuttall's Standard dictionary of the English language. By Nuttall, P.Austin. Published 1914. (verb) (v.) (verb)
To shut up in a pen, as stray cattle; confine; hold in the keeping of a court.
- The Winston Simplified Dictionary. By William Dodge Lewis, Edgar Arthur Singer. Published 1919. (verb) (v. t.) (verb transitive)
To shut up in a pound or pen; to confine; to shut in.
- Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874. (verb) (v.) (verb)
To confine, as in a pound: to restrain within limits: to take possession of.
- The american dictionary of the english language. By Daniel Lyons. Published 1899. (verb) (v. t.) (verb transitive)
To confine, as in a pound; take possession of.
- The Clarendon dictionary. By William Hand Browne, Samuel Stehman Haldeman. Published 1894. (verb) (v. t.) (verb transitive)

Usage examples:

I couldn't develop an irrigation system from any of the little streams that flowed down the Sierra, because there wasn't enough water, and there was no place to impound it, even if there had been sufficient water.
- The Long Chance by Peter B. Kyne
They resemble no cameras of my experience; I fear I shall have to impound
- Sjambak by John Holbrook Vance
If I could impress and impound him to marry Mary Paynham, I should be glad.
- The Complete Project Gutenberg Works of George Meredith by George Meredith