Medievel "meeting" room

They were usually referred to as the Great Hall, or the Hall.

Reception chamber. Council chamber.

Seems unlikely there would be a room just for meetings in an 11th c. castle, unless the room was specifically the office/study of a nobleman, or possibly a high-ranking servant. This kind of room would typically have been an antechamber of the person's bedroom (although I'm not sure if they built that way as early at the 11th c.), or if it was a small unattached room it might be called soandso's closet. You could also have a meeting in a sitting room or solar or dining room or chapel I guess, even outside if the weather was good. It depends what the meeting was about, usually it would be held in a location relevant to the topic.

"Great hall" would be the most likely name, in a castle. (And yes, it would be used for feasting as well.)

In a village, they might have a seperate meeting hall "The Guild Hall" - possibly maintained by the various guilds for meetings and even social activities.