Ballet Dictionary - American Ballet Theater: 170 terms from the book "Technical Manual and Dictionary of Classical Ballet," Dover Publications.
Ballet Terms A to Z: From learntodance.com.
Belly Dance Terms: Glossary with detailed definitions. Terms in several different languages.
Dolmetsch Online's Music Dictionary: Designed to help one understand the more common musical terms which are come across in a score or a book on music, including terms in other languages.
Encyclopedia of Microtonal Music Theory: By Tonalsoft, a software manufacturer. Includes introduction.
Glossary of Technical Theatre Terms: Contains many terms related to the technical aspects of theater, and terms of other related disciplines.
Glossary of Theatre Terms: Provides definitions of many technical theatre terms.
Grove Concise Dictionary of Music: Searchable entries, including definitions of musical terms, brief biographies of composers, performers and ensembles.
Indian Music Glossary: Glossary of terms used in Indian music.
Performing Arts Dictionary: Dictionary of terms associated with ballet, tap dancing and music.
Vance's Fantastic Tap Dance Dictionary: A complete glossary of tap dance, including names of steps and combinations, and descriptions of the movements associated with tapping.
Virginia Tech Multimedia Music Dictionary: A reference for musical terms, including some terms from other languages. Includes AIFF sound files for the pronunciation of each term and images for some terms.