An octave spans eight notes in the musical scale, and a standard piano keyboard includes seven full octaves across its 52 white and 36 black keys.
The word "octave" comes from the Latin root "octo," which means "eight." While an octave only includes seven unique notes, the title comes from the fact that it includes two variants of the same note on opposite ends of each individual octave. For example, an octave can begin with a "low C" and will conclude with a "high C" at the top of the octave. An octave on a piano spans the white keys, which play the major notes, but also includes five black keys, which play minor notes within the octave.