An algorithm is a well-defined sequence of instructions to solve a specific problem or perform a computation. It's a step-by-step procedure that always produces the correct result if followed correctly. Algorithms are used in computer science, mathematics, and other fields.

Key characteristics of an algorithm include:

• Finiteness: An algorithm must always terminate after a finite number of steps.
• Definiteness: Each step in the algorithm must be precisely defined and unambiguous.
• Input: An algorithm takes zero or more inputs.
• Output: An algorithm produces one or more outputs.
• Effectiveness: Each step in the algorithm must be basic enough that it can be carried out in principle by a person using only pencil and paper.

Here are some examples of algorithms:

• A recipe for baking a cake.
• A method for solving a mathematical equation.
• A computer program for sorting a list of names.