Yeshiva comes from "yoshev" -- the present tense, to sit verb. The term is, in America, used for schools which have a dual curriculum of secular and Judaic studies and stress the religious a bit more than what are called academies or day schools. Some yeshivas significantly downplay the secular studies and their graduates are more prepared to stay within the right wing jewish world. Others are more modern and try to act both as religious centers and prep schools. There is no one right formula for what a yeshiva is, what it sounds like inside, or its particular course of study.