lecture (v.) Look up lecture at Dictionary.com
1580s, "to read or deliver formal discourses," from lecture (n.). Transitive sense "instruct by oral discourse" is from 1680s. Meaning "to address severely and at length" is from 1706. Related: Lectured; lecturing.
lecture (n.) Look up lecture at Dictionary.com
c. 1300, "written works, literature;" late 14c., "learning from books," from Medieval Latin lectura "a reading," from Latin lectus, past participle of legere "to read," originally "to gather, collect, pick out, choose" (compare election), from PIE *leg- (1) "to pick together, gather, collect" (source also of Greek legein "to say, tell, speak, declare; to count," 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;" Albanian mb-ledh "to collect, harvest;" Gothic lisan "to collect, harvest," Lithuanian lesti "to pick, eat picking;" Hittite less-zi "to pick, gather"). To read is, perhaps, etymologically, to "pick out words."

The sense "a reading aloud, action of reading aloud" (either in divine worship or to students) in English emerged early 15c. That of "a discourse on a given subject before an audience for purposes of instruction" is from 1530s. Meaning "admonitory speech given with a view to reproof or correction" is from c. 1600. Lecture-room is from 1793; lecture-hall from 1832.