'tetragonal' originates from Greek, specifically the word 'tetragonos,' where 'tetra-' meant 'four' and 'gonia' meant 'angle.'

'tetragonos' transformed into the Latin word 'tetragonalis,' and eventually became the modern English word 'tetragonal' through Middle English.

Initially, it meant 'having four angles,' and this meaning has largely remained the same in modern usage.