| Value | Genre/Period |
|---|
| UNI | University Plays (1500-1642) [classed as genre and period] |
| ELIZ | Elizabethan (1580-1603) |
| JAC | Jacobean and Caroline (1603-1660) |
| REST | Restoration (1660-1700) |
| EEC | Early Eighteenth-Century (1700-1750) |
| LEC | Late Eighteenth-Century (1750-1800) |
| ENC | Early Nineteenth-Century (1800-1835) |
| MNC | Mid-Nineteenth-Century (1835-1870) |
| LNC | Late Nineteenth-Century (1870-1900) |
| ba | Burletta |
| bo | Ballad Opera |
| bsq | Burlesque |
| c | Comedy |
| co | Comic Opera |
| d | Drama |
| do | Dramatic Opera |
| ent | Entertainment |
| ext | Extravaganza |
| f | Farce |
| h | History |
| int | Interlude |
| leg | Classical Legend |
| m | Masque |
| o | Opera |
| p | Pantomime |
| pas | Pastoral |
| t | Tragedy |
| tc | Tragicomedy |