You don't mention which meal you are planning, but Boma only serves breakfast and dinner while Tusker House serves all three. Also, Tusker House is a character meal for breakfast.
As the PP said, Boma is at the Animal Kingdom Lodge, not the Animal Kingdom park. You will need to leave the AK and take a bus to the AKL if you want to go to Boma. The AKL is a beautiful place so a visit there might be a nice way to end your AK day.
If you are planning for breakfast I'd only go to Boma if you have your own car. Getting there with Disney transportation will be more time consuming, making the start to your AK day later. I'd just go to Tusker House instead.
So, my advice is Tusker House if you want breakfast or lunch and Boma if you want dinner.