Ascertain

1. v. t. To find out or learn for a certainty, by trial, examination, or experiment; to get to know; as, to ascertain the weight of a commodity, or the purity of a metal.
2. v. t. To render (a person) certain; to cause to feel certain; to make confident; to assure; to apprise.
3. v. t. To make (a thing) certain to the mind; to free from obscurity, doubt, or change; to make sure of; to fix; to determine.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.