'anisotropy' originates from Greek, specifically the word 'anisos,' where 'an-' meant 'not' and 'isos' meant 'equal,' combined with 'tropos' meaning 'turn' or 'way.'

'anisos' transformed into the French word 'anisotropie,' and eventually became the modern English word 'anisotropy' through scientific Latin.

Initially, it meant 'not equal in all directions,' and this meaning has largely remained the same in modern usage.