FASM, which stands for Flat Assembler, is a popular software that enables programmers to assemble x86 and x64 code. It is widely used in the development of operating systems, drivers, and other low-level applications. There are some synonyms for the word "FASM," including "assembler," "assembly language," and "machine code." Assembler is a general term used to describe any tool that converts assembly code into machine code. The assembly language is the system of programming that uses mnemonics to represent machine instructions. And machine code is the executable code that a computer can directly execute. All these synonyms encompass the idea of converting human-readable code to low-level machine code to make the software run efficiently.