“Going out” and “seeing someone” are both used in the relationship between two people. Although their meaning may be similar, they are not the same. Going out can mean going to a place for someone or a group of people. It can also mean to be dating someone.
You are seeing someone may also have several meaning. It can mean you have an appointment with someone. For example, “I’m seeing my doctor today for this headache.” Seeing someone can also mean being in a romantic relationship with someone. This doesn’t mean that you are necessarily exclusive. Hope you find this information helpful.
It can be different depending on whoever is saying it, but I personally believe whenever you say you are “seeing someone,.” It merely means you are hanging out with a person exclusively. This means that even if you are not officially together, you see each other often.
You are each other’s dates in some of the special moments of your life. When you are “going out,” this means that you are still getting to know each other. It is likely that you will go out with your friends too or you may be going out with different people because you are getting to know all of them. As long as you are not exclusively dating, this is not something that you have to be concerned about.