From Wiktionary, the free dictionary
From Cantonese 螄蚶 / 蛳蚶 (si1 ham1).
see hum (uncountable)
- (informal, Malaysia, Singapore) Blood cockles; ark clams (as food)
- Synonym: (Malaysia, Singapore) hum
2009, AleXX, soc.culture.singapore[1] (Usenet):See Hum should go with Laksa!! - Idiot!!