To discourse of, in speech or writing. Obsolete.

intransitive. To speak, treat, or argue (of a matter). Also in passive with non-referential it as subject. Obsolete.

intransitive. To discourse at length, enlarge (on, upon, †of a theme).

intransitive. Frequently with of, on, upon. To speak or write (in later use at length or formally) on a particular topic. Cf. discourse, n. 3a…

intransitive. To deliver a lecture or lectures. Also †to lecture it.

intransitive. To discourse, to preach, sermonize. (In quot. 1857 perhaps transitive. To preach to.)

intransitive. To discourse upon a particular subject; to make a dissertation. (Now, affected.)

intransitive. To deliver lectures, to ‘hold forth’.

intransitive. To deliver a sermon or address; to preach. Obsolete. rare.

intransitive. To preach; to speak publicly, discourse, harangue. (Usually somewhat contemptuous.)

To preach: = to hold forth at phrasal verbs (to hold forth 4 at phrasal verbs). Obsolete. rare.

To give serious exhortation, talk seriously; = preach, v. 1b. Also with it.

intransitive. To make a dissertation; to discourse; = dissert, v. 2. (Unusual.)