Lewis & Short

insŭlārĭus, ii, m. [insula].

  1. I. A tenant of an insula (post-Aug.), Petr. 95; Dig. 1, 15, 4; cf.: CERDO INSVLAR., Inscr. Orell. 2926.
  2. II. A slave who had charge of an insula, and collected the rents, Dig. 50, 16, 203; 7, 8, 16; 14, 3, 5 al.