a pos ‧ ter ‧ i ‧ o ‧ ri /ˌeɪ pɒsteriˈɔːraɪ, ˌɑː pɒsteriˈɔːri $ ˌɑː poʊstɪriˈɔːri, ˌeɪ pɑː-/ BrE AmE adjective , adverb formal
[ Date: 1500-1600 ; Language: Latin ; Origin: 'from what comes later' ]
using facts that you know now to form a judgment about what must have happened before
⇨ ↑ a priori