Instruction

An instruction is a form of information which is communicated in order to explain how an action, behavior, method, or task is to be begun, completed, conducted, or executed.

Computer architecture

In Computer architecture, an instruction is a single operation of a processor. The width of an instruction depends on the architecture of the platform, but it is usually from 4 to 64 bits wide. The content of an instruction is determined by the platform's Instruction Set Architecture (ISA), but it usually contains an opcode, which determines the type of instruction, register sources and destination operands, and maybe an immediate field.

Computer science

At a higher level, in computer science, an instruction could also be part of a computer program in a programming language; see also Procedure.

French law

In the context of French law (or inquisitorial systems based on France's), the instruction is the pre-trial phase of a criminal investigation that is led by a judge.