culm; hollow stem of a grass
Botanical term for the hollow jointed stem of grasses such as bamboo, rice, or wheat. Not an everyday word; used in technical or agricultural contexts.
The culm of a rice plant is hollow and has nodes.
The culm of bamboo is very strong and is used as a building material.
The kanji 稈 is composed of 禾 (grain) and 旱 (drought), but the historical derivation is uncertain. It is conventionally used for the hollow stem of grasses.