'anisotropically' originates from Greek, specifically the elements 'an-' + 'isos' + 'tropos', where 'an-' meant 'not', 'isos' meant 'equal' and 'tropos' meant 'turn' or 'way'.

'anisotropic' and related forms come from New Latin/Greek coinages used in scientific contexts (19th century), with the noun 'anisotropy' and adjective 'anisotropic' developing into modern English and the adverb formed by adding '-ally' to the adjective.

Initially it denoted 'not equal in all directions' (i.e., directional difference); over time the meaning has remained essentially the same but has been specialized in physics, materials science, and engineering contexts to describe directional dependence of specific physical properties.