Bass is the instrument and the part that mainly covers the low register, supporting the foundation of the chords and the center of gravity of the rhythm. The word covers electric bass as well as synth bass and upright bass.
The basic idea
Bass often moves using the root note of the chord as its guide. When its timing lines up with the kick, the foundation of the song becomes stable.
Playing and programming with it
Start by placing the chord roots on the beats, then adjust note lengths and rests. Listen to the kick and the bass alternately so the low end does not pile up.
How it differs from related terms
Bass is the role of the low-end part, while guitar is an instrument that more often handles accompaniment or lead. Both are string instruments, but their roles in a song differ.
Supporting the chords and the rhythm reliably, rather than moving in complicated ways, is the starting point of a good bass line.
