The IC is the Imum Coeli, and cusp of the 4th house. The AC is the ascendant, and cusp of the 1st house. They are two of the “angles” (the others are the MC or Midheaven opposite the IC, and the DC or descendant opposite the AC). The AC is calculated based on the sign on the horizon when you were born, and the IC is calculated based on Midheaven, which is (I think) where the parallel you are born in meets the ecliptic and … AH SCIENCE! I’m really not entirely sure. Sorry 😦
The IC represents your family roots and your past, including past conditioning. It’s sign indicates how you experienced your childhood and home life. The AC represents your physical body, but also your approach to the world, which is psychologically based on the role you took on in your family unit. These two angles, therefore, are linked by your childhood experience and family role.
So, for example, if you have a Capricorn IC, you experienced a cold, structured childhood with limits and responsibilities. Often, a Capricorn IC has a Libra AC. Libra risings are often mediators in their family unit, and at the very least expected to be socially correct, polite, graceful, placing social expectations at top priority. That’s not really an easy role for a child to take on. Even though Libra risings are admired for their looks and popularity, it might have taken them a lot of restriction, self-denial, and hard work. They never felt that parental nurturing, or had the chance to just be a selfish kid.
Now for a completely different IC sign: Gemini. This is the child that grew up self-taught because they were left to their own devices, and although Gemini represents siblings, they felt a disconnect. I have Gemini IC and I grew up with a brother 12 years older than me, a huge age gap. I also have half- and step- sisters, but we grew up in different households. Remember, the IC represents how you perceived your family and childhood, so a sibling of yours could have a very different perspective than you (and a different IC).
Gemini IC is the kid that reads and writes from an early age. They are creative and excel at using their hands, via musical instruments, Play-Doh, video games, etc. They multi-task, at home, and breeze through elementary school academically. School feels restrictive however, because they are a) too smart and therefore unstimulated, or b) shy/ostracized by other kids.
Gemini ICs often have Pisces AC. Pisces risings are the space-cadets of their families. Gemini IC develops a rich inner life because they feel unstimulated. Pisces risings develop a mind palace to play in, and seem otherworldly or lost in their own fantasies. They are imaginative and often have artistic or musical skills. Gemini IC often has issues with one parent, whom they are unable to communicate with, or don’t see eye to eye. Pisces risings frequently grow up with a parental lack that helps to shape their strong sensitivity/empathy for others.
What is your IC sign, and how do you think it shaped your AC? Maybe you have a Scorpio IC (if so, I’m sorry for your shitty childhood), which helped shape your enviable Leo rising (actually, not sorry because you’re probably attractive and popular). It’s good to make the connection from your upbringing to why you do what you do. It can help you realize that you bite people’s heads off because you grew up in a competitive household, or that you never say “no” because your parents helped everyone who came begging. But once you realize where the behavior stems from, if you don’t like it, leave it in the past where it belongs.