filtrate

Imagine brewing coffee: the liquid dripping into your mug has passed through a filter, while the grounds stay behind. In science, that liquid is called a *filtrate*. It is the part of a mixture that makes it through the filter.

It is not just about coffee. In a lab, a scientist may collect the *filtrate to get a clearer liquid without unwanted particles. Your kidneys also produce a filtrate as they begin to clean your blood. The word is mostly used as a noun, though in technical writing it can also appear as a verb meaning "to filter." So when a liquid passes through a barrier and the solid part stays behind, the part that comes through is the filtrate*.

A *filtrate is the liquid, and sometimes the gas, that has passed through a filter. In filtration, you start with a mixture and end up with two parts: the material that stays on the filter and the filtrate* that passes through it.

You will often see the word in science, medicine, and industry. In a laboratory, a chemist may filter a cloudy mixture and then study the *filtrate, which is the clearer part collected below. In the body, the kidneys produce what is called glomerular filtrate*, an early stage in the process of cleaning the blood. Water treatment works in a similar way, because water may pass through sand, charcoal, or other materials before the cleaned liquid moves on.

The verb form *filtrate exists, but it is much less common than filter and is mainly used in technical contexts. In everyday English, people usually say they filter water, coffee, air, or a solution, and then refer to the liquid that comes through as the filtrate. So the central idea is simple: something passes through a filter, something else is left behind, and the part that gets through is the filtrate*.