assembler

Short definition from Wiktionary

Noun

1. 1
   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. 2
   Assembly language.
3. 3
   One who assembles items.
4. 4
   A nanodevice capable of assembling nanodevices, possibly including copies of itself, according to a plan.