expression, noun
grassroots movement
Refers to a movement driven by ordinary people at the local level, rather than by leaders or centralized organizations.
その環境保護団体は草の根運動から始まった。
That environmental group started as a grassroots movement.
Compound of 草の根 (kusa no ne, 'grassroots', literally 'roots of grass') and 運動 (undō, 'movement').