Joining and association difference

Could anyone please explain the difference between “joining” (or rejoining) and “association” in Zigbee networks?
I thought they were quite the same but the below phrase found on the user guide is getting me high!
“If multiple rejoining attempts fail, or if NJ = 0xFF, the device attempts to join using association”
So please, what is the difference?
Many thanks,

They mean the same thing. Joining is the act of Associating where by Associated means that the Joining process is completed.

Joining and association is exactly the same.
Rejoining instead is different: it does not simply mean “join again”.
Rejoining is a procedure that allows an awaking end node to join its network if it does not find its parent device, even if permit-join is not enabled.
Digi descriptions are a bit misleading regarding this point.
There is a more extensive explanation of rejoin in the Digi Xbee User Guides.