the GNU version of the Collaborative International Dictionary of English
n. The faculty or capacity of the mind for forming ideas; the exercise of this capacity; the act of the mind by which objects of sense are apprehended and retained as objects of thought.
The Century Dictionary and Cyclopedia
n. The process or the act of forming ideas.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. the process of forming and relating ideas
Word Usage
"The word "ideation" also shows up in the phrase "suicidal ideation," meaning "thinking, often obsessively, about harming yourself.""