基层

basic level / grassroots unit / basement layer

(bound form) base; foundation / (bound form) radical (chemistry) / (bound form) gay (loanword from English into Cantonese, Jyutping: gei1, followed by orthographic borrowing from Cantonese)

to pile on top of one another / layer; stratum / floor (of a building); story / (math.) sheaf / classifier for layers