The bone of the arm (humerus) meets both the ulna (the inner bone of the forearm) and radius (the outer bone of the forearm) to form a hinge joint at the elbow. The radius and ulna also meet one another in the elbow to permit a small amount of rotation of the forearm.
The emigres were those who helped to spur on the revolution. People were tired of being poor and watching the royalty get richer without any work.
From the perspective of the country which they leave, they are called emigrant or outmigrant. Sociology designates immigration usually as migration (as well as emigration accordingly outward migration).