What does filtrate mean?
Filtrate is a noun denoting the liquid that has passed through a filter, particularly in chemistry, medicine, and industry, where the goal is to separate suspended solids from a fluid. When a suspension is poured through filter paper or a membrane, the solid particles are caught while the clarified liquid — the filtrate — collects beneath. The word belongs primarily to technical registers: laboratory protocols instruct researchers to collect, decant, or analyze the filtrate, and in physiology the term appears in phrases such as glomerular filtrate, describing fluid forced through the kidneys' filtering structures. It pairs conceptually with its opposite: the residue or precipitate left behind on the filter. Derived from the same Latin root as filter and filtration, filtrate is a precise, useful term for anyone working with separations, offering a single word for what would otherwise require a cumbersome phrase like 'the filtered liquid.'
nounThe liquid that has passed through a filter, especially one from which solid particles have been removed. In laboratory and industrial contexts, it is the clarified fluid produced by the process of filtration.
- The clear liquid that has passed through a filter, having had its suspended solids removed (used chiefly in chemistry, medicine, and industry).
"After several passes through the filter paper, the filtrate ran clear into the flask below."
"The technician carefully decanted the filtrate into a clean beaker for further analysis."
"Kidney function is assessed by comparing the composition of the blood to the glomerular filtrate."
Rarely pluralized except when comparing multiple filtered samples in laboratory contexts.
"The two filtrates were combined before the solvent was evaporated."
In chemistry, what you want is often not what you started with — the filtrate is the prize that drips through while everything else gets left behind.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of filtrate
Filtrate derives from Medieval Latin filtrare, meaning 'to filter,' which itself comes from filtrum, the Latin word for felt — the material originally used to strain liquids. The English noun emerged in scientific usage around the early seventeenth century as chemistry and alchemy developed standardized separation techniques. It shares this root with filter, filtration, and infiltrate, all tracing back to that humble piece of felted cloth.
Related word forms
How filtrate is actually used
Filtrate is a technical term, used almost exclusively in scientific, medical, laboratory, and industrial writing rather than everyday conversation. It always refers to the fluid that has passed through a filter, never to the solid matter retained.
Easily confused with filtrate
A filter is the material or device through which fluid passes, while the filtrate is the liquid that has already passed through it.
Residue is the solid material left behind on the filter, whereas the filtrate is what flows through.