What term describes a sermon or a moralistic lecture?

The term that describes a sermon or a moralistic lecture is "homily." A homily is typically a short, informal speech or sermon that conveys moral direction or spiritual teaching, often based on a biblical text. It aims to provide practical application of religious principles to everyday life, making it relevant to the audience.

In contrast, a parable is a simple story used to illustrate a moral or spiritual lesson, but it is not specifically a sermon or lecture. Exegesis refers to the critical interpretation of a text, especially religious texts, focusing more on analysis than the delivery of moral teachings. A monologue, while it can involve moral themes, is generally a long speech by a single character in drama or literature and does not necessarily carry the ecclesiastical connotations of a sermon.