Definition

Noun: A common name for a periodical cicada (Magicicada spp.) native to North America. This insect is known for its extraordinarily long, synchronized, subterranean juvenile (nymph) stage, which lasts 13 or 17 years, after which the adults emerge en masse in vast numbers.

Usage Notes

• The term "seventeen-year locust" is a colloquial name. Scientifically, it is not a true locust (which is a type of grasshopper) but a cicada.
• It is used specifically to refer to the broods (regional populations) of periodical cicadas whose life cycle is precisely 17 years. There are also 13-year broods, sometimes called "thirteen-year locusts."
• The defining characteristic is the mass, synchronized emergence of adults after their long developmental period.

Examples

• The deafening sound in the forest was caused by the emergence of the seventeen-year locust.
• Scientists study the seventeen-year locust to understand its unique biological clock and synchronized life cycle.
• My grandfather remembers the last major emergence of the seventeen-year locust in this county.

Advanced Usage

• The phenomenon is often used metaphorically to describe any event that occurs at long, regular, and predictable intervals.
  • Their family reunions are like the emergence of the seventeen-year locust—rare but impossible to miss.

Variants and Related Words

• Periodical cicada: The formal, scientific term for the insect.
• Magicicada: The genus name for periodical cicadas.
• Thirteen-year locust: The common name for broods with a 13-year life cycle.
• Cicada: The broader family of insects to which the periodical cicada belongs.
• Brood: A term for a geographically distinct population of periodical cicadas that emerge in the same year (e.g., Brood X).

Synonyms

• Periodical cicada

Notes on Meaning

While "seventeen-year locust" is the traditional common name, it contains a technical inaccuracy: 1. "Seventeen-year": Correctly describes the length of the life cycle for specific broods. 2. "Locust": A misnomer. True locusts are swarming, short-horned grasshoppers. Cicadas are a different order of insects (Hemiptera) known for their loud mating calls produced by tymbals, not for swarming for migration. The name persists due to historical observation of their massive, "swarm-like" emergences.

Noun

1. North American cicada; appears in great numbers at infrequent intervals because the nymphs take 13 to 17 years to mature