tr.v., -tained, -tain·ing, -tains.
- To discover with certainty, as through examination or experimentation. See synonyms at discover.
- Archaic. To make certain, definite, and precise.
[Middle English acertainen, to inform, from Old French acertener, ascertain- : a-, to (from Latin ad-; see ad-) + certain, certain; see certain.]
ascertainable as'cer·tain'a·ble adj.ascertainableness as'cer·tain'a·ble·ness n.
ascertainably as'cer·tain'a·bly adv.
ascertainment as'cer·tain'ment n.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
