Crossword clue: a fixed star, in medusa's head, in the constellation perseus, remarkable for its periodic variation in brightness.
1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).
Possible answers
algol
5 letters
web-def
(from a combination of ALGOrithmic and Language); a programming language used to express computer programs as algorithms