cent
One hundredth of a semitone, the unit for measuring tiny differences in tuning.
One hundredth of a semitone, the fine ruler for tuning. A hundred cents is one semitone; twelve hundred is an octave. The gap that makes the circle of fifths fail to close is about 23 cents, just under a quarter step, small but audible.
Learn it: The math behind music
The one-sentence definition at the top is the same one the Theory Aide extension shows as a tooltip inside Ableton Live. Hover any dotted term for its own.