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Planetarium

/ˌplænɪˈtɛəriəm/noun

A domed theatre in which images of the night sky are projected onto the ceiling.

The Greek roots

πλανήτης
planḗtēs
wanderer

Literally: place of the wanderers

The story of the word

The Greeks called the planets astēres planētai, wandering stars, because they drifted against the fixed pattern while everything else held station. Planetarium was coined in Latin for the clockwork orreries of the eighteenth century, brass models of that wandering, and only moved to the dome after Zeiss built the first projector in Munich in 1923.

How it travelled
Ancient Greek → Modern Latin → English
First recorded
18th century

The same roots elsewhere

Other languages reached for exactly the same Greek pieces.

Same family

planetplanetaryaplanatic

In a sentence

The planetarium ran the same show at four o'clock every Saturday of my childhood.

Built on the same root

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