'selection' originates from Latin, specifically the word 'selectio', where 'se-' meant 'apart' and 'legere' meant 'to choose'; 'exam' (short for 'examination') originates from Latin, specifically the word 'examen', where the root referred to a 'weighing' or test used to judge.

'selection' changed from Old French and Middle English forms such as 'selectioun' and eventually became the modern English word 'selection'. 'exam' evolved from Latin 'examen' through Old French/Medieval Latin and Middle English forms such as 'examen' and 'examyn' into the modern 'exam'/'examination'.

Initially, 'selection' referred generally to the act of choosing and 'examen' referred to a weighing or test; over time the compound/phrase came to mean specifically 'choosing by means of an examination' (selection conducted on test results).