From assemble + -er.

• IPA: /əˈsɛmb(ə)lɚ/

assembler

1. (programming, countable) A program that reads source code written in assembly language and produces executable machine code, possibly together with information needed by linkers, debuggers and other tools.
2. (computer languages, informal, mostly, uncountable) Assembly language.

   I wrote that program in assembler.

3. (countable) One who assembles items.
   • 2014, Howard Waldrop, Things Will Never Be the Same: A Howard Waldrop Reader:

     Our father worked as an assembler in a radio factory that would go out of business in the early 1960s, […]

4. (nanotechnology, countable) A nanodevice capable of assembling nanodevices, possibly including copies of itself, according to a plan.
   • w:Assembler (nanotechnology) on Wikipedia.Wikipedia

• (language) assembly, assembly language

• assemble
• assembly

• French: assembleur
• German: Assembler
• Portuguese: montador
• Russian: ассемблер

• Portuguese: montador

• Portuguese: montador molecular