The term, and its Italian version 'cognoscento' (plural cognoscenti), derives from the latin verb 'to know'. A connoisseur is a collector and/or art lover who is knowledgeable about works of art, in the sense of being able to recognise characteristic individual or regional styles.

This skill is based on familiarity with a large number of pictures, and the ability to retain a visual memory of them.

Connoisseurship is the basis of stylistic attribution, but is now rarely used in isolation; additional technical or documentary proof is usually sought. The most famous connoisseur of this century was Bernard Berenson (1865 - 1959), who studied the 'schools' of Italian art.