adverb

mainly.

he is remembered chiefly for his organ sonatas

mainly,in the main,primarily,principally,predominantly,above all,mostly,for the most part,first and foremost,especially,particularly,essentially,substantially,usually,customarily,habitually,typically,commonly,generally,on the whole,largely,by and large,as a rule,in most instances,almost always,almost entirely,to a large extent,to a great degree