The psychological result of perception and learning and reasoning.
The action or faculty of knowing; knowledge, consciousness; acquaintance with a subject.
Oxford English Dictionary
In science, cognition is the set of all mental abilities and processes related to knowledge: attention, memory and working memory, judgement and evaluation, reasoning and “computation”, problem solving and decision making, comprehension and production of language, etc.
Cognition is the act of thinking, perceiving, and understanding.
Processes of knowing, including attending, remembering, and reasoning; also the content of the processes, such as concepts and memories.
American Psychological Association
Cognition, the process involved in knowing, or the act of knowing, which in its completeness includes perception and judgment. Cognition includes all processes of consciousness by which knowledge is accumulated, such as perceiving, recognizing, conceiving, and reasoning. Put differently, cognition is an experience of knowing that can be distinguished from an experience of feeling or willing. It is one of the only words that refers to the brain as well as to the mind.