Simple Definition:
Knowledge is the understanding and awareness gained through learning, experience, or study. [Understanding means to comprehend or grasp the meaning of something. Awareness means to be conscious or knowledgeable about something. Learning means acquiring knowledge or skills through study or experience.]
For example, if you learn how to ride a bicycle, you gain knowledge of how to balance and pedal. Similarly, if you study about different countries, you acquire knowledge about their cultures and traditions.
Very Simple Definition:
Knowledge is what we know and understand. It comes from learning, experience, or studying.
For example, when we read a book or listen to a teacher, we gain knowledge. When we touch something hot and get burned, we learn not to touch it again.