'baffleplate' originates from modern English as a compound of 'baffle' and 'plate'. 'baffle' (English) is used in the sense 'to check or deflect', and 'plate' (English) means 'a flat piece of metal or other material'.

'baffle' in English developed from earlier senses influenced by French 'bafouer' (to mock) and later English uses meaning 'to frustrate' or 'to check'; by the 19th century it was applied to devices that obstruct or redirect flow. 'plate' comes from Old French 'plate' (flat) and Late Latin 'plattus'. These elements combined in technical English to form the compound 'baffle plate' (often written as one word in some technical contexts) describing a plate used as a baffle.

Initially, 'baffle' carried senses like 'to mock' or 'to frustrate', but over time it shifted to physical senses of 'to check, block, or redirect'—leading to the compound meaning 'a plate that blocks or redirects flow'.