The Latin decubitus (meaning lying down) is related to cubitum (the elbow) reflecting the fact the Romans habitually rested on their elbows when they reclined. Adult Skin Problems Slideshow Quiz: Is Ringworm Contagious?
In music theory, an interval is the difference between two pitches. An interval may be described as horizontal, linear, or melodic if it refers to successively sounding tones, such as two adjacent pitches in a melody, and vertical or harmonic if it pertains to simultaneously sounding tones, such as in a chord.
An octave is a type of musical interval, or measure of distance between two notes. Specifically, an octave is the distance between one note and another note with the same letter name. An octave on a keyboard. Count from the note labeled C to the next note labeled C -- that's an octave. You might have noticed that that distance spans eight of the keyboard's white keys (including the two Cs themselves).