Webster's Revised Unabridged Dictionary · 1913

Teach

Teach (tēch) , transitive verb

[Old English techen, imp. taughte, tahte, Anglo-Saxon tacean, imp. tahte, to show, teach, akin to tācn token. See Token.]

1.
To impart the knowledge of; to give intelligence concerning; to impart, as knowledge before unknown, or rules for practice; to inculcate as true or important; to exhibit impressively; as, to teach arithmetic, dancing, music, or the like; to teach morals.
If some men teach wicked things, it must be that others should practice them. — South
2.
To direct, as an instructor; to manage, as a preceptor; to guide the studies of; to instruct; to inform; to conduct through a course of studies; as, to teach a child or a class.
He taught his disciples. — Mark ix. 31
The village master taught his little school. — Goldsmith
3.
To accustom; to guide; to show; to admonish.
I shall myself to herbs teach you. — Chaucer
They have taught their tongue to speak lies. — Jer. ix. 5

This verb is often used with two objects, one of the person, the other of the thing; as, he taught me Latin grammar. In the passive construction, either of these objects may be retained in the objective case, while the other becomes the subject; as, I was taught Latin grammar by him; Latin grammar was taught me by him.

Teach , intransitive verb

To give instruction; to follow the business, or to perform the duties, of a preceptor.
And gladly would he learn, and gladly teach. — Chaucer
The priests thereof teach for hire. — Micah iii. 11