How about if you compared it to a "12-bar blues"?
This is a common form with a fixed pattern [though with a billion variations]. It was the simple building block upon which all "Rock & Roll" was constructed, though it has many more forms that that.
4 bars of root chord, 2 bars of the 4th, 2 bars of the root
1 bar of the 5th, one bar of the 4th, 1 bar of the root, [1 bar of the 5th or stay on the root, optional].
Because it's so ubiquitous in 20th century Western music, it of course has more variations than could ever be listed.
If you remove all except the root & 5th in each chord [& probably even remove the 5th & just play the sequence of root notes], all Western musicians would still recognise it & be able to play along.
Played by a band, everybody knows the structure - you don't change that ever.
Though you probably never actually play the same thing twice, only the form remains the same, the contents change with every iteration.
Once as an intro, then once as a vocal passage, then a solo, then some more vocals, then someone else gets a solo… & round & round it goes until someone decides to call an end.
I've seen drunken open mic nights where this can go round for an hour, with people getting on & off stage as they decide they need another beer or another chance to shine.
Let's call it … informal.
So, 12 bars of an immutable chord sequence.
The bar is the bit that you count, "1, 2, 3, 4"
The cycle is each section of 12 bars.
A phrase is harder to define - maybe, any melodic structure played by any one player, that could be done in one breath [even if the instrument doesn't breathe].
I'll let the man himself close the show
"Well, it's a one for the money…"