Inflected forms: pl. as·sem·blies 1a. The act of assembling. b. The state of being assembled. 2. A group of persons gathered together for a common reason, as for a legislative, religious, educational, or social purpose. 3.Assembly The lower house of the legislature in certain U.S. states. 4a. The putting together of manufactured parts to make a completed product, such as a machine or electronic circuit. b. A set of parts so assembled. 5. A signal by bugle or drum for troops to come together in formation. 6.Computer Science The automatic translation of symbolic code into machine code. 7.Computer Science An assembly language.