knowledge /ˈnɑːlɪʤ/ noun
Learner's definition of KNOWLEDGE
: information, understanding, or skill that you get from experience or education
[noncount] : awareness of something : the state of being aware of something

common knowledge

: something that many or most people know

public knowledge

: something that people know because it has been reported in the news

safe/secure in the knowledge

: feeling safe or secure because you know something specified

to someone's knowledge

: according to what someone knows usually used in negative statements

to the best of my knowledge

used to say that you think a statement is true but that there may be something you do not know which makes it untrue