Eighty (adjective)

1. Constituting number eighty in a sequence.
2. Ten times eight.

Origin:

From middle english eighty, eightitþi, ahtetiȝ, ahetig, from old english eahtatig, æhtatig, eahtatig, from proto-germanic *ahtatigaz, from *ahtô (“eight”), from proto-indo-european *oḱtṓw (“eight”) + *-tigjô (“group of ten”), from *deḱm̥t (“group of ten”), from *deḱm̥ (“ten”).

Examples:

1. The temperature outside is eighty degrees Fahrenheit.
2. The library has eighty copies of the book in stock.
3. The athlete broke the world record by running eighty meters in under ten seconds.
4. The family is planning to celebrate their grandfather's eightieth birthday.
5. The cost of the new smartphone is eighty dollars.