Founded (6)
'founded' is the definition.
(synonyms)
This is all the clue.
(Other definitions for based that I've seen before include "Worthless" , "Established" , "Positioned" , "Founded, grounded" , "Located" .)
(Other definitions for rooted that I've seen before include "Firmly established and well planted" , "Fixed in place like plants in soil" , "Frivolousness" , "(Of new cutting) firmly established" , "Firmly attached as plants are to ground" .)