Earth's rotation is the rotation of Planet Earth on its own axis, with the terrestrial axis being the imaginary line that passes through the poles. The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where Earth's axis of rotation meets its surface, while the South Pole is the other point where Earth's axis of rotation intersects its surface, in the Southern Hemisphere. Here on the left a beautiful image of our Planet Earth with the northern hemisphere in view, the Arctic sea ice and clouds (public domain, source: NASA/Goddard Space Flight Center via Wikimedia Commons).
The Earth rotates eastward, in prograde motion (prograde means the direction of rotation is same as that of the sun, the central hub of our system, which is in the counter-clockwise direction when viewed from the north pole, while the retrograde rotation means the direction of rotation is opposite to that of the sun, e.g. the clockwise rotation). As viewed from the north pole star Polaris, the Earth turns counter clockwise as represented in the animation showing the rotation of Earth on its own axis (image by Wikiscient via Wikimedia Commons, CC BY-SA 3.0 license or GFDL). The Earth's motion around its own axis has a defined duration, i.e. the period to make a complete rotation on its axis, which is called day. Actually, there are different types of "day" depending on the measurement reference adopted. The concept of day commonly in use, with each day consisting of 24 hours, is a mere scientific convention unrelated to the effective duration of the Earth day.
In the video here below made by Alex Rivest a beautiful star timelapse revealing the Earth’s rotation: by using software to track the stars and keep them still, the rotation of the earth is revealed. These time-lapses were taken in Anza-Borrego State Park, Joshua Tree National Park, Maine, New Hampshire, Massachusetts, Tibet, Hawaii, Tonga and Yellowstone.
The days for all the planets and any objects rotating around the Sun are the following:
The sidereal day, i.e. the time the Earth needs to rotate once on its axis referring to the stars. Since the stars can be considered fixed, as being very far, therefore the day is the time when these stars reappear at the same point in the sky after the full rotation of the Earth. The duration is exactly 23h 56m 04s.
The true solar day, the period of time during which the Earth completes one rotation on its axis with respect to the Sun. Considering the apparent motion of the Sun to an observer on the Earth, we can say that the solar day represents the time interval in which the Sun passes through the same point on the meridian considered by the observer. It depends on the Earth's orbital motion, and it is thus affected by changes in the eccentricity and inclination of Earth's orbit. Both vary over thousands of years, so the annual variation of the true solar day also varies.
The solar day is longer than the sidereal one, as the Earth does not only rotate, but also shift due to its revolution motion around the Sun. Earth moves a little less than a degree around the Sun during the time it takes for one complete rotation on its axis. So, for the Sun to appear on the same meridian in the sky again after one full axial rotation, the Earth has to rotate one extra degree (0,986 degrees per day) to bring the Sun into the same apparent meridian in the sky. So, in simple words, the Earth must rotate nearly 361 degrees to let it appear that the Sun has done 360 degrees in the sky. Actually, to return to the same point towards the Sun, the Earth must compensate for the distance travelled along the orbit during the day (1 degree), with an additional rotation, that requires more than just 4 minutes (it takes (24 h / 360 °) * 0 °, 986 = 3m 56s).
For all planets that rotate in the same direction of their revolution around the Sun, the solar day is longer than the sidereal day by about 4 minutes. Continuing to add four minutes every day, after 6 months the sidereal day indicates noon, whereas the solar day indicates midnight. For this reason, the sidereal day is not considered for the measurement of time. Moreover, the solar day is not constant, as further explained in the next paragraph on the Earth’s Revolution.
The average of the true solar day during an entire year is called the mean solar day, or civil day, which contains 86,400 mean solar seconds, and is the calendar day of constant duration of 24 hours, thus used in the computation of time matching the need to define a day of exactly 24 hours, as the average durations of all the days of the year (this could happen if the Earth had a perfectly circular orbit around the Sun). According to this day we have definitions of minutes and seconds, as the 86,400th part of the mean solar day (24 hours x 60 minutes x 60 seconds = 86,400 seconds in a day).
The image below illustrated the comparison between the sideral day and the solar day (source: Gdr/Chris828 via Wikimedia Commons). On a prograde planet (i.e. revolving in the same sense as the rotation of the Sun) like the Earth, the sidereal day is shorter than the solar day. At time 1, the Sun and a certain distant star are both overhead. At time 2, the planet has rotated 360° and the distant star is overhead again (1→2 = one sidereal day). But it is not until a little later, at time 3, that the Sun is overhead again (1→3 = one solar day). More simply, 1-2 is a complete rotation of the Earth, but because the revolution around the Sun affects the angle at which the Sun is seen from the Earth, 1-3 is how long it takes noon to return (text source: Wikipedia).