To conceptualize is to form an idea of something — to take a messy thing in the world and make a clear picture of it in your mind, often so you can talk about it, plan it, or study it. You can conceptualize a problem before you try to solve it. A designer conceptualizes a product before drawing the final version. Though actually, this is a formal, academic verb. In daily talk people say think through, picture, or work out the idea. American English likes conceptualize with a z; British English often writes conceptualise with an s. Same meaning. It is not quite the same as imagine for fun: conceptualize usually means you are trying to get the idea clear enough to use, not just daydream.