An interrupt is like an urgent message sent from one part of the computer to another. It signals that something important has happened and needs immediate attention from the part receiving the interrupt. A trap is a specific type of interrupt created by software. It's used to signal two things: either there's something unusual going on$,$ like trying to access data that doesn't exist, or the program needs a special service from the operating system, like reading a file. User programs can create traps, though not all programming languages let you do this directly. Some languages, like Ada, C$,$ and Java, allow programmers to create traps. In C$,$ traps are called "signals". Traps are used to tell the CPU that something unusual has happened in the software, or that the program needs a special service. Then, the CPU can either stop the program, or pause what it's doing and switch to a special part of the code to handle the situation.