c.1200, from Anglo-Fr., O.Fr. sumundre "summon," from V.L. *summundre "to call, cite," from L. summonere "hint to," from sub "under" + monere "warn, advise" (see monitor). Summons "authoritative call to be at a certain place for a certain purpose" is late 13c., from O.Fr.
sumunse, noun use of fem. pp. of somondre. Summoner "petty officer who cites persons to appear in court" is from early 14c.; contracted form sumner is from mid-14c.