I am not a native English speaker, but I often see grass roots/grassroots/grass-roots used in sentenses like: Recovery efforts have been made at the grass roots level. The grassroots network helped the community improve the environment. The global movement to raise awareness on climate change was started as a small grassroot campaign.

Hi Mary, The word "grass roots" means "the source of something". Forexample, you should solve the problems at the grass roots. This means you need to find the original source that causes the problems and try to solve it from there (so that no more future problems get created).

public community / people / population / the masses, / everyday folks, etc.