D defs.my
Entry 3 senses Webster, 1913

Circus

/sẽrk'-əs/ · Cir·cus · IPA /ˈsɝkəs/
01 n. A level oblong space surrounded on three sides by seats of wood, earth, or stone, rising in tiers one above another, and divided lengthwise…
pl. Circuses ((#))
  1. 1.
    A level oblong space surrounded on three sides by seats of wood, earth, or stone, rising in tiers one above another, and divided lengthwise through the middle by a barrier around which the track or course was laid out. It was used for chariot races, games, and public shows.(Roman Antiq.)
  2. 2.
    A circular inclosure for the exhibition of feats of horsemanship, acrobatic displays, etc. Also, the company of performers, with their equipage.
  3. 3.
    Circuit; space; inclosure.[R.]
    “The narrow circus of my dungeon wall.” Byron.