Comprehensible means able to be understood. When your teacher explains a math concept in a way that makes sense to you, the explanation is comprehensible. When a book is written clearly enough for readers to follow the story and ideas, it's comprehensible.

The opposite is incomprehensible, meaning impossible to understand. You might find a college physics textbook incomprehensible because it uses terms and concepts you haven't learned yet. Or you might find someone's handwriting so messy that their note is incomprehensible.

What makes something comprehensible depends on who's trying to understand it. A chemistry textbook might be perfectly comprehensible to a scientist but incomprehensible to a first-grader. Good teachers and writers work hard to make their ideas comprehensible to their specific audience. They break down complex ideas, use clear examples, and avoid unnecessary jargon.