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Why is Halley’s Comet called a periodic comet?

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Illustration showing the eight planets of the solar system in order from the Sun-Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune-depicted to scale by size, with labeled diameters in miles and kilometers. The Sun is partially visible on the left for comparison. — Solar system The planets (in comparative size) in order of distance from the Sun.

Halley’s Comet is classified as a periodic comet because it moves around the Sun in a closed orbit, returning at regular, predictable intervals.12

The comet is named after the English astronomer Edmond Halley, who in 1705 analyzed historical records and determined that comets observed in 1531, 1607, and 1682 shared similar orbits. He correctly hypothesized that these were the same object returning approximately every 76 years. This discovery was significant because it demonstrated that at least some comets are members of the solar system and follow predictable paths.3

In modern astronomical terminology, the designation "P/" before a comet's name indicates that it is periodic, meaning it has an orbital period of fewer than 200 years. Halley’s Comet is officially designated as 1P/Halley, signifying it was the first comet to be recognized as periodic. While its average orbital period is 76 years, the gravitational influence of planets can cause this duration to vary between 74.5 and 79 years.23