A mnemonic is a term, symbol or name used to define or specify a computing function. Mnemonics are used in computing to provide users with a means to quickly access a function, service or process, bypassing the actual more lengthy method used to perform or achieve it. Assembly language also uses a mnemonic to represent machine operation, or opcode.
Techopedia explains Mnemonic
In computer programming, routine programming functions are assigned a mnemonic that is shorter in length but provides the same functionality as the original function.
In assembly language, mnemonics are used to specify an opcode that represents a complete and operational machine language instruction. This is later translated by the assembler to generate the object code. For example, the mnemonic MOV is used in assembly language for copying and moving data between registers and memory locations.