from https://www.legatomusiccenter.com/the-difference-between-acoustic-analog-electric-and-digital/:
“Acoustic” refers to musical instruments that produce sound naturally, without the use of electronics.
“Electric” refers to musical instruments that use electricity to produce sound, either by amplifying an acoustic instrument or by generating sound directly through the use of electronic components.
“Digital” refers to musical instruments that use digital technology to produce and process sound, which is technology that uses binary code (a series of 1s and 0s) to represent and process information, as opposed to analog technology, which uses continuous signals to represent information.