Knowledge (noun)

1. Facts, information, and skills acquired by a person through experience or education; the theoretical or practical understanding of a subject.
2. Awareness or familiarity gained by experience of a fact or situation.
3. The body of truth, information, and principles acquired by mankind.

Origin:

Middle english: from old english cnāwleð, from cnāwan "to know" + -leð "-ness".

Examples:

1. He has a vast knowledge of music.
2. She has knowledge of the subject.
3. He acquired knowledge from his studies.
4. Her knowledge of the subject impressed us.
5. He has a lot of knowledge about cars.