'interpretable' originates from Latin, specifically the verb 'interpretari', where 'interpret-' meant 'explain, translate, expound'.

'interpretari' passed into Medieval Latin and Old French forms and into Middle English as 'interpret' (with related nouns 'interpretation'), and the adjective 'interpretable' was formed in English by adding the suffix '-able' to indicate capability.

Originally associated with the act of explaining or translating, the core idea shifted to describe that which can be explained or given an interpretation; the capability sense (able to be interpreted) became established.