Green’s Dictionary of Slang

knowledge box n.

1. [late 18C+] (also knowledge bag, knowledge bump, knowledge conk) the head or the mind [UK use faded by early 19C but revived in US black use by 20C+].

2. [late 19C] used of a clever individual.

3. [20C+] (US, also house of knowledge, knowledge factory, knowledge stash) a school.