Kastomkastom Kastom is a pidgin word (Bislama/English) used to refer to traditional culture, including religion, economics, art and magic in Melanesia. The word derives from the Australian English pronunciation of 'custom'. Kastom is mostly not written, only passed down through teachings and stories and includes places, stories, objects and animals and plants. is a pidgin word (Bislama/English) used to refer to traditional culture, including religion, economics, art and magic in Melanesia. The word derives from the Australian English pronunciation of ‘custom’. Kastom is mostly not written, only passed down through teachings and stories and includes places, stories, objects and animals and plants.