(Especially in critical writing) the genre of mystery stories set in a rural English village; (the generic name for) a typical English village as the setting for a violent crime; frequently attributive, as "Mayhem Parva school", etc.
1970s; earliest use found in Colin Watson (1920–1982). From mayhem + classical Latin parva, feminine singular of parvus little, after English village names with this as second element (e.g. Ash Parva, Shropshire, Ashby Parva, Leicestershire, etc.).