As an adjective, heuristic (pronounced hyu-RIS-tik and from the Greek "heuriskein" meaning "to discover") pertains to the process of gaining knowledge or some desired result by intelligent guesswork rather than by following some preestablished formula. (Heuristic can be contrasted with algorithm ic.) The term seems to have two usages:
1) Describing an approach to learning by trying without necessarily having an organized hypothesis or way of proving that the results proved or disproved the hypothesis. That is, "seat-of-the-pants" or "trial-by-error" learning.
2) Pertaining to the use of the general knowledge gained by experience, sometimes expressed as "using a rule-of-thumb." (However, heuristic knowledge can be applied to complex as well as simple everyday problems. Human chess players use a heuristic approach.)
As a noun, a heuristic is a specific rule-of-thumb or argument derived from experience. The application of heuristic knowledge to a problem is sometimes known as heuristics .