Lewis & Short

circŭlo, āre, v. a. (post-class. collat. form of circulor) [circulus],

  1. I. to make circu lar or round, App. flor. 9, p. 346, 21. circulatus gressus, Cael. Aur Tard. 1, 1: digitos. bent in, App. Mag. 89, p. 330.
  2. II. Esp., to encircle, encompass: verticem varietatibus, Mart. Cap. 7, § 728: sideribus, id. 8, § 831; 4, § 333 al.; cf. Neue, Formenl. 2, p. 269.