The term 'concept' is used to describe a broad range of ideas, from the abstract to the concrete. CONCEPTION (10 letters) is the act of forming an IDEA or concept in the mind. CONCEIT (7 letters) is an overly favorable opinion of oneself or one's abilities. BRAINSTORM (10 letters) is a group activity in which members generate ideas and solutions to a problem. THEORY (6 letters) is an explanation or set of principles that are used to explain a phenomenon. HYPOTHESIS (10 letters) is a proposed explanation for a phenomenon that can be tested through experimentation. UNIT (4 letters) is a single element of a larger whole. IMAGE (5 letters) is a representation of something, either real or imagined. IDEA (4 letters) is a thought or suggestion as to a possible course of action. NOTION (6 letters) is a general understanding or belief about something. Mentalpicture (13 letters) is a mental representation of a person, object, or scene.