From grass + tops, by analogy with grassroots.
grass tops (not comparable)
- (idiomatic) Of, related to, or involving local influential figures.
1998, Dan Clawson; Alan Neustadtl; Mark Weller, Dollars and Votes: How Business Campaign Contributions Subvert Democracy, Philadelphia, Pa.: Temple University Press, ISBN 978-1-56639-625-7, page 12:
- Along with the ads, industry worked to mobilize local politicians and business executives in what business groups called a "grass tops" campaign.
- (idiomatic, plural only) People in a position of power or influence at a local level.
- plural of grass top.