The term 'not open to the public' can be summarized by the word 'PRIVATE', which has seven letters. This term is used to describe something that is not accessible or available to the general public, such as a PRIVATE event or a PRIVATE residence. It can also refer to information that is not meant to be shared with the public, such as PRIVATE conversations or PRIVATE documents. In general, PRIVATE means that something is not open to the public and is only accessible to a select few.