A frequent error among non-astronomers is the mixup of these two words when talking about the movement of the Earth or another planet. They are two different phenomena. A planet rotates around its axis, but revolves around the Sun. One rotation equals one day. One revolution equals one year. As an amateur astronomer, let’s hope you’re never confused about which is which!

While we’re on the subject, note that the Earth rotates west to east. That’s why the Sun, stars and other objects rise in the eastern sky -- our apparent horizon is "falling" toward the east and "rising" in the western sky. What we refer to as a "day" is a solar day; that is, it counts the time between two consecutive meridian transits of the Sun, which moves across our sky due to the Earth’s rotation. But the revolution of the Earth around the Sun also causes the Sun to shift position in our sky with respect to the background stars by approximately one degree per day in an easterly direction. Thus, to complete a full day from one meridian transit to another, the Earth must rotate that additional degree, or about four minutes of time each day, which is incorporated into our familiar 24-hour day. However, a sidereal day measures the time between consecutive meridian transits of a star. A sidereal day is shorter than a mean solar day by just under that four minutes, since the apparent positions of stars are largely unaffected by the Earth’s revolution around the Sun.