Lecture

[lek-cher] /ˈlɛk tʃər/

noun
1.
a speech read or delivered before an audience or class, especially for instruction or to set forth some subject:
a lecture on Picasso’s paintings.
2.
a speech of warning or reproof as to conduct; a long, tedious reprimand.
verb (used without object), lectured, lecturing.
3.
to give a lecture or series of lectures:
He spent the year lecturing to various student groups.
verb (used with object), lectured, lecturing.
4.
to deliver a lecture to or before; instruct by lectures.
5.
to rebuke or reprimand at some length:
He lectured the child regularly but with little effect.
/ˈlɛktʃə/
noun
1.
a discourse on a particular subject given or read to an audience
2.
the text of such a discourse
3.
a method of teaching by formal discourse
4.
a lengthy reprimand or scolding
verb
5.
to give or read a lecture (to an audience or class)
6.
(transitive) to reprimand at length
n.

late 14c., “action of reading, that which is read,” from Medieval Latin lectura “a reading, lecture,” from Latin lectus, past participle of legere “to read,” originally “to gather, collect, pick out, choose” (cf. election), from PIE *leg- “to pick together, gather, collect” (cf. Greek legein “to say, tell, speak, declare,” originally, in Homer, “to pick out, select, collect, enumerate;” lexis “speech, diction;” logos “word, speech, thought, account;” Latin lignum “wood, firewood,” literally “that which is gathered”).

To read is to “pick out words.” Meaning “action of reading (a lesson) aloud” is from 1520s. That of “a discourse on a given subject before an audience for purposes of instruction” is from 1530s.
v.

1580s, from lecture (n.). Meaning “to address severely and at length” is from 1706. Related: Lectured; lecturing.