Different people/coaches are going to have different jargon.
In my mind, each 5/3/1 three week cycle is a “Wave.” The first three weeks, you work your way through all the different sessions. During the next three week “wave” to try to surpass what you did in the first wave. So week 1 will be 5’s week with Jokers. During the next “wave,” your 4th week will again be 5’s week, with Jokers. Ideally, you’ll do more reps, 5 pounds higher, and then do your Jokers a little heavier, or whatever.
After 2 cycles of the 5/3/1 scheme, or 2 three week waves, you’ll change things up. That “period” or block or mesocycle or whatever you want to call it has come to an end.
You could then switch to 5’s Pro, with Boring But Big for awhile. You’d use your training max, calculated from your Pr sets, and Wendler’s percentages. so there would be no guess work. Then you’d progress in a different way for awhile.
All of this is optional. None of these ideas or terms are mandatory. Its just useful to have some kind of way to get your head around this stuff. The more specific you can be, the easier it is to make sure you keep the important stuff in your program.
Some dudes do this real naturally.
Arnold power lifted for awhile. Then he Olympic lifted for awhile. Then he was a body builder. During one period of time, he focused on his upper chest. During another period of time, he worked on his calves. But no matter what he focused on, he always also had big guns and a wide back.
He got up at 5 in the morning, to do 1000 pound calf raises with Reg Park. This way, they wouldn’t have to waste time in their real training sessions with that stuff.
He did front squats, after squats to hit his quads more. As a tall dude, he used front squats as “special exercise” after squatting to hit a weakness.
After he worked up, pyramid style on the bench press for awhile, he switched and made big jumps to a top weight for awhile.
He called it “muscle confusion.”