bytecode

Any compiled instruction code that is intended for a virtual machine: Java is the most popular example, but even Perl can be compiled to bytecode. The name suggests that instructions are typically represented as a byte each, as opposed to regular machine code where instructions are usually several bytes long.

Emacs elisp (and most other lisp implementations) also use bytecode. Some interpreted versions of BASIC, such as Applesoft, tokenized the code into bytecode. The UCSD P-code was sort of an early bytecode system.

Note that while the instructions in bytecode may be just a byte, bytecode may also contain strings, integers, floats, etc., which will be stored in their binary, native formats for the language (which are most probably a word or longer).