Lewis & Short

ferrūmen (fērū-), ĭnis, n. [ferrum].

  1. I. Cement, solder, glue (post-Aug.): quod furto calcis sine ferumine suo caementa componuntur, Plin. 36, 23, 55, § 176; Petr. 102; Dig. 41, 1, 27.
    Transf.: esse videtur Homeri (versus) simplicior et sincerior, Vergilii autem ϝεωτερικώτερος et quodam quasi ferumine immisso fucatior, etc., i. e. connection, connecting word, Gell. 13, 26, 3.
  2. * II. Iron-rust: (crystalla) infestantur plurimis vitiis, scabro ferumine, maculosa nube, etc., Plin. 37, 2, 10, § 28.