F / ferrūmen
noun

ferrūmen

gen. ferrūmĭnis · gender neuter · decl. 3rd
(), , ferrum.
Cement; solder; glue by extension
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. —*
Iron-rust
Iron-rust: (crystalla) infestantur plurimis vitiis, scabro ferumine, maculosa nube, etc., Plin. 37, 2, 10, § 28.