noun
triangular sink strainer; sink corner strainer
A small triangular container placed in the corner of a kitchen sink to collect food scraps; often has a mesh or slotted bottom for draining.
三角コーナーにたまった生ゴミを捨ててください。
Please throw away the food scraps that have collected in the sink strainer.
水切り is a general term for draining or a draining tool; 三角コーナー specifically refers to the triangular sink-corner strainer.
Compound of 三角 (さんかく, 'triangle') and コーナー ('corner'), describing its shape and typical placement in the sink corner.