1. To deliver a sermon or a religious speech to an assembled group of people, typically in a church: "The pastor preached to a large congregation."
2. To proclaim or to teach; such as, a religious message or belief: "Every Sunday morning, the well-known religious leader was preaching to many people in the church and to even more during his television program."
3. To earnestly advocate a belief or a course of action: "May's parents have always preached toleration and moderation in all things."
4. To give moral advice to someone in an annoying or pompously self-righteous way: "The audience wants to be entertained, not to be preached at."
5. Etymology: from late Old English predician, a loan word from Church Latin, borrowed in the 12th century as preachen; from Old French prechier; from Late Latin predicare, "to proclaim publicly, to announce"; from Latin prae-, "forth" + dicare, "to proclaim, to say".