A big group is a large gathering of people, usually consisting of more than 10 individuals. A 'PASSEL' is a slang term for a large group, typically consisting of 6 or more people. An 'ARMY' is a large military force, usually consisting of thousands of soldiers. A 'BEVY' is a large group of people, usually consisting of 4 or more people. An 'OCTET' is a group of 8 people. All of these terms can be used to describe a big group.