'predicate' originates from Latin, specifically the word 'praedicatus' (past participle of 'praedicare'), where 'prae-' meant 'before' and 'dicare' (related to 'dicere') meant 'to proclaim/declare or to say.'

'predicate' changed from Latin 'praedicare'/'praedicatus' through Medieval Latin and Old French forms (e.g. Old French 'prediquer') and entered Middle English (e.g. 'predicaten'), eventually becoming the modern English word 'predicate'.

Initially it meant 'to proclaim or declare' (and in grammar to 'say of' or 'attribute to the subject'); over time it evolved into the modern senses of 'to assert/state' and the derived adjectival sense 'based on' (as in 'predicated on').