IL Castiglioni Mariotti is a highly regarded Latin-Italian and Italian-Latin dictionary that has been used by students and scholars for decades. The application includes searchable sections for both languages, featuring over 50,000 Latin entries and 30,000 Italian entries. The dictionary also includes bending tables of nominal Latin voices and verbals, linguistic and antiquarian appendices, and extensive textual documentation of classical and Christian Latin, literary, and epigraphic styles.

One can download a free trial version of the app, which allows access to words starting with the letter A only. To access the complete dictionary, users can purchase a license directly from the app or create an account and enter the unlock code present on the label of the CD-ROM sold together with the printed copies of the fourth edition. Once downloaded, the dictionary can be accessed offline.