'grader' originates from English, specifically from the word 'grade' plus the agentive suffix '-er' (meaning 'one who does').

'grade' came into English from Old French/Medieval Latin forms related to Italian 'grado' and Latin 'gradus'. The Latin 'gradus' meant 'step' and evolved into words meaning rank or degree; adding the English suffix '-er' produced 'grader' meaning 'one who gives grades or ranks'.

Initially, the root 'gradus' meant 'step'; over time the sense shifted to 'rank' or 'degree' and then to 'to assign a rank or mark', so 'grader' came to mean 'one who assigns marks or ranks'.