Aldehyde ("Á-to-hāi-toh", "A-lú-té-hí-toh") sī chi̍t khoán iú-ki hòa-ha̍p-bu̍t, hâm kò͘-chō −CHO ê koan-lêng-thoân (functional group).

Aldehyde structure
Aldehyde structure