You can find dictionaries for use in the library in the reference collection on the first floor. Some dictionaries are also available for checkout in the circulating collection on B2. Here are the call number ranges if you want to browse
English PE 1628
French PC 2640
Italian PC 1625
Spanish PC 4640
German PF 3625
Chinese PL 1455
Japanese PL 678
Greek PA 445
Latin PA 2365
Arabic PJ 6640
Persian PK 6379
Russian PG 2640
Look up the meaning of words in this updated, online version of the Oxford English Dictionary. It's particularly useful when researching the etymology of a word. (Oxford)
Search for Latin words in this dictionary that covers all the Latin texts from the classical period up to about 600 A.D. (De Gruyter)
*Create an account to access the full corpus of the database. Access a collection of Greek literature from Homer to the fall of Byzantium in AD 1453. Note: The database has been designed as a searchable linguistic database, not a browsable library. (University of California)