Did you know that there are two zodiacs?
The difference between them is largely a question of measurement and how and where to begin measuring. Volumes have been written and it’s not necessary for our purposes here to go into it in any detail.
The tropical zodiac is mostly used by western astrologers and looks at the sky with reference to the solstice and equinox points. Then they divide the sky up into twelve sections that may or may not be equal, depending on other data points.
The sidereal zodiac is primarily used by eastern astrologers and is more closely related to the actual placement of the stars in their constellations.
The actual difference between these two zodiacs is approximately 23 degrees depending on which astronomer you consult. This difference is called the ayanamsa.
Both groups use the same names ie. Aries, Taurus, Gemini, etc.
As an astrologer, I can’t help but think that the Sidereal folks are more connected to ‘reality’ since they are looking at the sky as it is, rather than observing it as a mathematical construct. But those same astrologers have yet to acknowledge Uranus, Neptune, and Pluto in their interpretations. For them Saturn is an absolute boundary. Regardless, both systems work. Time & experience have established that fact, conclusively. 
All said, I have had many wonderful discussions with astrologers of both systems. Aside from it’s practical or impractical uses, just the study, alone, of astrology helps to balance out a lot of mis-thinking that goes on in the world.