parent taro corm; mother taro tuber
Refers to the central, older corm of a taro plant from which smaller side corms (子芋) grow. Used in agricultural and culinary contexts.
When you plant the parent taro corm, smaller side corms grow around it.
This dish uses the mother taro corm.
Compound of 親 (oya, 'parent') and 芋 (imo, 'tuber'). The exact historical derivation is uncertain, but the term transparently describes the central parent corm of the taro plant.