Programs written by humans in a high-level language (such as Python or Java) are not directly understood by a computer's processor, which can only execute instructions in machine code (binary). A special program called a language translator converts the human-written code into a simpler form the machine can run.
A compiler is one such translator. It takes the entire source program written in a high-level language and translates it, all at once, into machine code (or another lower-level form) that the computer can execute directly. Because it converts the whole program from a complex, human-readable language down into the simple binary instructions the hardware executes, it fits the description of translating a program into a simpler language the computer can run.
An interpreter also translates code but does so line by line as the program runs, rather than producing a complete translated program beforehand; while related, this distinguishes its mode of operation. A processor is the hardware component that executes instructions rather than a translation program itself, and an algorithm is simply a step-by-step procedure for solving a problem, not a translation tool at all.
Exam reminder: compilers and interpreters are both language translators, but a compiler translates the entire program in one pass before execution, which matches the description of converting a full program into a simpler executable form.