1a group of people gathered togethe

1a group of people gathered together in one place for a common purpose:
an assembly of dockers and labourers
a group of people elected to make laws or decisions for a particular country or region:
the 577-seat National Assembly
the UN General Assembly
2 [mass noun] the action of gathering together as a group for a common purpose:
a decree guaranteeing freedom of assembly
the regular gathering of the teachers and pupils of a school at the start or end of the day:
he was told off for talking in assembly
(usually the assembly) chiefly historical a signal for troops to assemble, given by drum or bugle.
3 [mass noun, often as modifier] the action of fitting together the component parts of a machine or other object:
a car assembly plant
[count noun] a unit consisting of components that have been fitted together:
the tail assembly of the aircraft
4 [mass noun, usually as modifier] Computing the conversion of instructions in low-level code to machine code.