An algorithm is a set of instructions or steps to solve a problem, while pseudo code describes the algorithm without using the syntax of a specific programming language. Pseudo code cannot be executed by a computer. The key difference between an algorithm and pseudo code is that an algorithm is written in a natural language, while pseudo code uses structures from programming languages but not their exact syntax. Pseudo code makes it easier to transform an algorithm into actual computer code compared to an algorithm written only in a natural language.