Adding to David's excellent explanation the B can also be called as a passing chord. A passing chord is any chord(s) that connects two diatonic chords:

https://en.wikipedia.org/wiki/Passing_chord

PS - I have a guitarist friend who calls anything other than a 1-4-5 chord a "b a s t a r d" chord!


Whenever I get something stuck in the back of my throat, I dislodge it by drinking a beer.
It's called the Heineken Maneuver.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware