wellhole
/'welhəʊl/
📖 中文释义
- 井道; 井底水仓; 垂直大炮眼; 井筒
📘 English Definition（英文释义）
- n. The open space in a floor, to accommodate a staircase.
- n. The open space left beyond the ends of the steps of a
- staircase.
- n. A cavity which receives a counterbalancing weight in
- certain mechanical contrivances, and is adapted also for other
- purposes.