'brain-teaser' originates from the combination of 'brain' and 'teaser,' where 'brain' refers to the mind and 'teaser' implies something that provokes or challenges.

'brain-teaser' evolved from the concept of 'teasing the brain' with challenging puzzles or problems.

Initially, it referred to any problem that teased or challenged the mind, and this meaning has largely remained the same in modern usage.