Cite
 
sync: /sink/, vi.

(var.: synch)

1. To synchronize, to bring into synchronization.

2. [techspeak] To force all pending I/O to the disk; see flush, sense 2.

3. More generally, to force a number of competing processes or agents to a state that would be ‘safe’ if the system were to crash; thus, to checkpoint (in the database-theory sense).