........ Pants is the common term around here. No one uses trousers or slacks unless they are selling them or think they are impressing someone. Jeans are jeans, but mostly pants. Nice pants are "dress pants."
Perhaps unsurprisingly, East TN & surrounding area was/is the same way.....
Trousers were the pants that Brits wore;
Slacks were the fancy-ish not-quite-dress pants that women wore to family reunions, weddings, other similar things;
Jeans were almost always Blue Jeans, even if a different color - just calling them "jeans" implied "the good pair" that men would wear to the same sort of things where women would wear slacks......