Half a step behind Middle C.
Bb is the 3rd black key out of the grouping of 3. this is the same for every octave of Bb.
Bb is B flat as typed on a keyboard.
Why the window key in keyboard?
keyboard
The key of Bb means the tonic, or begining note of the scale, is a Bb. All the notes in the scale are based on Bb. The notes go like this- Bb-C-D-Eb-F-G-A-Bb. Nearly every song in the key of Bb end on Bb. It is what the song centers around and defines what notes you can use in a song.
Bb. an acoustic guitar can play in any key, like a piano.
If your keyboard is missing a key, press the key-less spot very lightly when used, or try to place the key back on, or at best get a new keyboard.
COMPUTER KEYBOARD KEY MEANINGS
To make an apostrophe on a keyboard, press the key beside the "enter" key on the right hand side of the keyboard.
It is usually on the key above the Enter (or Return) key on the keyboard.
A#/Bb
Bb or F