Lewis & Short

Pĕtīlĭus, a, name of a Roman gens.
Hence,

  1. A. Pĕtīlĭus, a, um, adj., of or belonging to a Petilius, Petilian: lex, Liv. 38, 55.
  2. B. Pĕtīlĭānus, a, um, adj., Petilian: regna, i. e. the villa of a certain Petilius, otherwise unknown, Mart. 12, 57, 19.