Colander in the context of Salad leaves

Filtration is a physical separation process that separates solid matter and fluid from a mixture using a filter medium that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter medium are described as oversize and the fluid that passes through is called the filtrate. Oversize particles may form a filter cake on top of the filter and may also block the filter lattice, preventing the fluid phase from crossing the filter, known as blinding. The size of the largest particles that can successfully pass through a filter is called the effective pore size of that filter. The separation of solid and fluid is imperfect; solids will be contaminated with some fluid and filtrate will contain fine particles (depending on the pore size, filter thickness and biological activity). Filtration occurs both in nature and in engineered systems; there are biological, geological, and industrial forms. In everyday usage the verb "strain" is more often used; for example, using a colander to drain cooking water from cooked pasta.

Oil filtration refers to the method of purifying oil by removing impurities that can degrade its quality. Contaminants can enter the oil through various means, including wear and tear of machinery components, environmental factors, and improper handling during oil changes. The primary goal of oil filtration is to enhance the oil’s performance, thereby protecting the machinery and extending its service life.

A sieve (/ˈsɪv/), fine mesh strainer, or sift is a tool used for separating wanted elements from unwanted material or for controlling the particle size distribution of a sample, using a screen such as a woven mesh or net or perforated sheet material. The word sift derives from sieve.

In cooking, a sifter is used to separate and break up clumps in dry ingredients such as flour, as well as to aerate and combine them. A strainer (see colander), meanwhile, is a form of sieve used to separate suspended solids from a liquid by filtration.

Leaf vegetables, also called leafy greens, vegetable greens, or simply greens, are plant leaves eaten as a vegetable, sometimes accompanied by their petioles and shoots, if tender. Leaf vegetables eaten raw in a salad can be called salad greens, whereas leaf vegetables eaten cooked can be called pot herbs.

Nearly one thousand species of plants with edible leaves are known. Leaf vegetables most often come from short-lived herbaceous plants, such as lettuce and spinach. Woody plants of various species also provide edible leaves.

Leaf vegetables, also called leafy greens, vegetable greens, or simply greens, are plant leaves eaten as a vegetable, sometimes accompanied by their petioles and shoots, if tender. Leaf vegetables eaten raw in a salad can be called salad greens, whereas leaf vegetables eaten cooked can be called pot herbs.

Nearly one thousand species of plants with edible leaves are known. Leaf vegetables most often come from short-lived herbaceous plants, such as lettuce and spinach, but also come from some woody plants.