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 elect), from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')." Thus to read is, perhaps, etymologically, to "pick out words."
The sense of "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. In Greek the words still had the double senses relating to "to speak" and "to gather" (apologos "a story, tale, fable;" elaiologos "an olive gatherer").
Proto-Indo-European root meaning "to collect, gather," with derivatives meaning "to speak" on the notion of "to gather words, to pick out words."
It forms all or part of: alexia; analects; analogous; analogue; analogy; anthology; apologetic; apologue; apology; catalogue; coil; colleague; collect; college; collegial; Decalogue; delegate; dialect; dialogue; diligence; doxology; dyslexia; eclectic; eclogue; elect; election; epilogue; hapax legomenon; homologous; horology; ideologue; idiolect; intelligence; lectern; lectio difficilior; lection; lector; lecture; leech (n.2) "physician;" legacy; legal; legate; legend; legible; legion; legislator; legitimate; lesson; lexicon; ligneous; ligni-; logarithm; logic; logistic; logo-; logogriph; logopoeia; Logos; -logue; -logy; loyal; monologue; neglect; neologism; philology; privilege; prolegomenon; prologue; relegate; sacrilege; select; syllogism; tautology; trilogy.
It is the hypothetical source of/evidence for its existence is provided by: 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 legere "to gather, choose, pluck; read," lignum "wood, firewood," literally "that which is gathered," legare "to depute, commission, charge," lex "law" (perhaps "collection of rules"); Albanian mb-ledh "to collect, harvest;" Gothic lisan "to collect, harvest," Lithuanian lesti "to pick, eat picking;" Hittite less-zi "to pick, gather."
early 15c., "voluntary," from Late Latin electivus, from elect-, past-participle stem of eligere "to pick out, choose" (see election). In U.S., in reference to school subjects studied at the student's choice, first recorded 1847. As a noun, from 1701.
late 14c., "a place where cardinals meet to elect a pope," also "the assembly of cardinals to elect a pope," from Italian conclave, from Latin conclave "a private room, chamber suite," probably originally "a room which may be locked," from assimilated form of com "with, together" (see con-) + clavis "a key" (from PIE root *klau- "hook"). Extended sense of "any private assembly" is by 1560s.