What is a familiar?

thanks for the help im trying to summon a astral familiar as i have yet to be able to get a physical one

I don't know if this is how it works or not, but it seems to work for me and maybe it could help others?

My familiar is a dolphin, but since I can't keep a dolphin in my house, I wear a necklace with a dolphin on it as a placeholder. It works for me- without it on, I can't focus on my spells and they usually turn out stronger when I have the necklace on (probably because of the focus). I also find that I have less encounters with negativity when I have it on.

I might have this whole familiar thing messed up. I never really got into the topic, but I'd really love if you could tell me if this is the same thing as a familiar or not?
Thanks!

To me, it sounds like a familiar. Your rituals and spells tend to feel stronger when you are thinking of the dolphin. A familiar is almost a visual representation of your magick or energy. In less words, I think so :)