The Collaborative International Dictionary of English v.0.48:

Procere \Pro*cere"\, a. [L. procerus tall.]
   Of high stature; tall. [Obs.] --Evelyn.
   [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

PROCERES. The name by which the chief magistrates in cities were formerly
known. St. Armand, Hist. Eq. 88.