Full Idea
Concepts are more or less definite groups of sensations that arrive together.
Gist of Idea
Concepts are rough groups of simultaneous sensations
Source
Friedrich Nietzsche (Unpublished Notebooks 1885-86 [1886], 34[086])
Book Reference
Nietzsche,Friedrich: 'Fragments from 1885-86 (v 16)', ed/tr. Del Caro,Adrian [Stanford 2020], p.23
A Reaction
I like this because I favour accounts of concepts which root them in experience, and largely growing unthinking out of communcal experience. Nietzsche is very empirical here. Hume would probably agree.