A sieve is a tool with a mesh or perforated bottom that separates materials by size. When you pour something through a sieve, smaller particles fall through the holes while larger pieces stay behind.

In cooking, you might use a sieve to remove lumps from flour or to rinse foods like fruits or vegetables. Bakers sift flour through a fine sieve to make it lighter and fluffier. Gold miners once used sieves to separate tiny gold flakes from river sand and gravel, shaking the sieve so the worthless sand fell through while the heavier gold remained.

The word also works as a verb: to sieve something means to pass it through a sieve. Scientists might sieve soil samples to sort particles by size, which helps them understand what the soil contains.

People use sieve metaphorically too. If someone has a “memory like a sieve,” they forget things easily, as if information pours through their mind like water through holes. When researchers sieve through old documents, they're carefully sorting to find what matters. The image of separation is key: a sieve lets the unnecessary pass through while catching what you need.