What is the meaning of Pentathlon?

An ancient athletics discipline, featuring five events: stadion, wrestling, long jump, javelin and discus

Ellipsis of women's pentathlon (“a 20th-century athletics discipline for women, the women's counterpart of the men's decathlon, the predecessor to the women's heptathlon, featuring five events: hurdles, shot put, high jump, long jump, and a run”).

Ellipsis of modern pentathlon, a discipline with five events based on late-19th century basic military skills.

pentathlon (discipline made up of five events)

pentathlon

Source: wiktionary.org