Suppose that you are at your aunt's or uncle's house for dinner with your family. Not really for fun. It's just a common gathering talking together with relatives. In fact you are a guest. Suddenly your girlfriend or boyfriend calls you. You answer the phone and say this sentence to him/her:
Hi, Sarah/Alex. May I call you back later? I'm at a party and can't talk to you very well.
My question is whether I can use the word party in this context, or is it (party) mostly used when you have a lot of fun?