Question about the vulkan specification on semaphore signal operations

In section 7.4.1.Semaphore Signaling of vulkan specification,

“When a batch is submitted to a queue via a queue submission, and it includes semaphores to be signaled, it defines a memory dependency on the batch, and defines semaphore signal operations which set the semaphores to the signaled state.”

What are operations in this sentence?And what is the difference between pipline stages and operations?Is this semaphore signal operation inserted into queue and wait to be executed like stages which a CommandBuffer consists of?