pivot; central point
Refers to the central pin or axis of a folding fan, and by extension any crucial central element.
The pivot of the folding fan came off.
vital point; cornerstone; keystone
Metaphorical extension of the fan pivot: the most important part or person that holds everything together.
He is active as the cornerstone of the team.
This policy will be the keystone of the reform.
Japanese photinia
A plant name (Photinia glabra). Usually written in kana as かなめ, and often referred to as かなめのき or 要黐.
See also: かなめもち
Japanese photinia is often used for hedges.
He is the key player who serves as the team's linchpin.
In negotiations, it's important to grasp the key point.
She is the one carrying the pivotal role in the project.
The pivot of the fan broke, so it can no longer be opened and closed.