council (n.)

c. 1200, "advice or instruction given;" c. 1300, "mutual advising or interchange of opinions, consultation," from Old French counseil "advice, counsel; deliberation, thought" (10c.), from Latin consilium "plan, opinion," from assimilated form of com "with, together" (see con-) + root of calare "to announce, summon" (from PIE root *kele- (2) "to shout"). As a synonym for "lawyer, one who gives legal counsel," attested late 14c.

"a member of a council," early 15c., an alteration of counselor by assimilation to council.

The distinction of form and sense ( councilor, one of a council, counselor, one who counsels) is modern; there is no OF. or L. form corresponding to councilor (L. as if *conciliarius) as distinguished from counselor (L. consiliarius). [Century Dictionary]

*kelə-, Proto-Indo-European root meaning "to shout." Perhaps imitative.

It forms all or part of: acclaim; acclamation; Aufklarung; calendar; chiaroscuro; claim; Claire; clairvoyance; clairvoyant; clamor; Clara; claret; clarify; clarinet; clarion; clarity; class; clear; cledonism; conciliate; conciliation; council; declaim; declare; disclaim; ecclesiastic; eclair; exclaim; glair; hale (v.); halyard; intercalate; haul; keelhaul; low (v.); nomenclature; paraclete; proclaim; reclaim; reconcile.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit usakala "cock," literally "dawn-calling;" Latin calare "to announce solemnly, call out," clamare "to cry out, shout, proclaim;" Middle Irish cailech "cock;" Greek kalein "to call," kelados "noise," kledon "report, fame;" Old High German halan "to call;" Old English hlowan "to low, make a noise like a cow;" Lithuanian kalba "language."