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.
Consonance and dissonance. Intervals are traditionally considered either consonant or dissonant. Consonant intervals are usually described as pleasant and agreeable. Dissonant intervals are those that cause tension and desire to be resolved to consonant intervals. These descriptions relate to harmonious intervals. In music theory, consonances are traditionally divided into two groups: perfect and imperfect. Perfect intervals (1, 4, 5, 8) are perfect consonances, as seen in the polyphonic music of the Middle Ages.