- Logeion – Provides simultaneous lookup of entries in the many reference works that make up the Perseus Classical collection and, in addition to definitions, includes frequencies, collocations, usage examples, and more.
- Liddell and Scott’s Greek Lexicon (download) (Android app) (iPhone app)
- Lewis and Short’s Latin Dictionary (download) (Android app) (iPhone app)
- Lexidium (iPhone app based on Lewis and Short)
- Autenrieth’s Homeric Dictionary (download)
- Smyth’s Greek Grammar (download) (iPhone app)
- Allen and Greenough’s Latin Grammar (download) (iPhone app)
- Smith’s Dictionary of Greek and Roman Antiquities (Download)
- Smith’s Dictionary of Greek and Roman Biography and Mythology (Download)
- Smaller Classical Dictionary (Download)
- Theoi – Encyclopedia of classical mythology and gods.
- Smith’s Dictionary of Greek and Roman Geography (Abacaenum – Hytanis)
- Smith’s Dictionary of Greek and Roman Geography (Labadius – Zymethus)
- Princeton Encyclopedia of Classical Sites
- Perseus Encyclopedia – A classical encyclopedia from the Perseus Project that provides very brief entries linked to the source materials that mention them.