Perfuse is from Latin perfusus, past participle of perfundere ('to pour over, drench'), from per- ('through, over') + fundere ('to pour'). Important recorded forms include perfundere (Latin) and fundere (Latin). Morphologically, the word preserves a built structure whose named elements carry the historical sense into English. The modern sense remains close to that composition, with the parts narrowing into a single lexical item. In current use it covers to spread or pour a fluid through or over something. The wider family includes derived forms such as perfusion and related words such as diffuse, infuse, transfuse, and perfusion.