その
その · sono · JLPT N5 · na-adj
that
so-no = so (that, near you) + no (linking particle): that ... of yours
Japanese pointing words share a set: ko- (near me), so- (near you), a- (far), do- (which). Add no and it must sit before a noun: sono hon = that book near you. Same family as kono, ano, dono.