noun
full flush; one-suit hand
Mahjong term: a winning hand composed entirely of tiles from a single suit. Also used figuratively for something uniform or homogeneous.
from Chinese qīng yī sè
彼は清一色で上がった。
He won with a full flush.
このプロジェクトのメンバーは清一色のエンジニアだ。
The members of this project are all engineers, a homogeneous group.
noun
Extended use from mahjong: describes a situation where everything is of the same kind or from the same source, often in manufacturing or team composition.
この製品は清一色の国産部品で作られている。
This product is made entirely from domestically sourced parts.