Lewis & Short

commūnītĭo, ōnis, f. [1. communio].

  1. I. Abstr., the making or preparing of a way; trop. = Gr. ὁδοποίησις: anne autem principium aut rei totius, quae agetur, significationem habere debebit, aut aditum ad causam et communitionem, etc., Cic. de Or. 2, 79, 320.
  2. II. Concr., a fortification, Vitr. 10, 13, 1.