noun
stagnancy; stillness
Describes a state of water or atmosphere that is calm, still, and without movement; often used for pools or deep, quiet parts of a river.
川のとろみに小魚が集まっている。
Small fish are gathering in the still pool of the river.
湖面はとろみを帯びて、鏡のようだった。
The lake surface was still and mirror-like.
The word is likely related to the mimetic root とろ (torotoro), suggesting slowness or thickness, but the exact derivation is uncertain.