Final answer:
The note between the bass and treble clefs is middle C, represented on a short ledger line and useful for piano learners.
Step-by-step explanation:
The note that is located on the invisible line between the bass and treble clefs is middle C. When you look at a grand staff, which combines both the treble and bass clefs, middle C can be notated just below the treble clef or just above the bass clef on a short line called a ledger line, which is often thought of as an invisible line between the two clefs. This is especially useful to know when you are learning to play the piano, where this specific knowledge is a key fundamental.