1.
an assembling or coming together of a number of persons, usually for a particular purpose:
The principal will speak to all the students at Friday's assembly.
2.
a group of persons gathered together, usually for a particular purpose, whether religious, political, educational, or social.
3.
(often initial capital letter) Government. a legislative body, especially the lower house of the legislature in certain states of the U.S.:
a bill before the assembly; the New York State Assembly.
4.
Military.
a signal, as by drum or bugle, for troops to fall into ranks or otherwise assemble.
the movement of forces, tanks, soldiers, etc., scattered by battle or battle drill, toward and into a small area.
5.
the putting together of complex machinery, as airplanes, from interchangeable parts of standard dimensions.
6.
Machinery. a group of machine parts, especially one forming a self-contained, independently mounted unit.