The crossword solution for the term BIT FOR AN ACCELERATOR is ION. An ION is an atom or molecule that has a net electric charge due to the loss or gain of one or more electrons. Ions are created when an atom or molecule gains or loses electrons in order to become more stable. They are important in many areas of science, including chemistry, physics, and biology. In accelerators, ions are accelerated to high speeds and used to study the structure of matter.