There are 4 elements in astrology - fire, earth, air, and water - and all 12 signs of the Zodiac fall in one of the four elements. The element a sign is in can give you insight into the energy and focus of that sign, but it also can show the other signs that sign is compatible with because of elemental affinity.
The signs of the same element can get along better with one another than with the other signs because you have the same base elemental energy. We often like the people who connect with the element of our Sun, Moon, or Rising.
The connections tend to be strongest among the Sun, Moon, and Rising, but you can also gauge compatibility by comparing the rest of your planets and houses to the planets and houses of someone else.
If you have many planets and points in the same element (like both of your Venuses are in earth signs, both of your Mars are in water signs, both of your Moons are in air signs, etc.), this can be someone you can get along well with, be attracted to, or at least understand.
Fire sign compatibility
Aries, Leo, and Sagittarius are the fire signs, the ones with a lot of energy to burn, extra enthusiasm and positive outlooks, and who love to be active. Bring fire signs together, and they want to get creative, have fun, and take action.
You can understand this about one another, and get along well. If you have one of these signs as your Sun, Moon, or Rising sign, you may feel you like the people who are also of the fire element.
Check out: Fire Signs in Astrology & Love
Earth sign compatibility
Taurus, Virgo, and Capricorn are the earth signs, the ones who are practical and down-to-Earth. Earth signs can take their time, have practical outlooks, and keep things steady. Bring earth signs together, and they can get things done, work hard, and ground us all.
You don’t feel the need to push each other outside of your element, and can stay by each other’s side. If you have one of these signs as your Sun, Moon, or Rising sign, you may feel you like earth element people.
Check out: Earth Signs in Astrology & Love
Air sign compatibility
Gemini, Libra, and Aquarius are the air signs, the ones who think logically about everything, are super engaging, and love to be sociable. Bring air signs together, and they can make it interesting, get you thinking, and brainstorm ideas.
You can operate with sharp minds and wits, and get that about one another. If you have one of these signs as your Sun, Moon, or Rising sign, you can be drawn to fellow air element people.
Check out: Air Signs in Astrology & Love
Water sign compatibility
Cancer, Scorpio, and Pisces are the water signs, the ones guided by emotion and intuition, and who connect to subtle energies. Bring water signs together, and they can intuit each other’s needs, show compassion and understanding, share with one another, and offer support.
You can find connections beyond the mental and physical. If you have one of these signs as your Sun, Moon, or Rising sign, water element people can feel like who you want.
Check out: Water Signs in Astrology & Love