time capsule

WordReference Random House Unabridged Dictionary of American English © 2026

time′ cap′sule, 

1. a receptacle containing documents or objects typical of the current period, placed in the earth or in a cornerstone for discovery in the future.

• 1935–40

Collins Concise English Dictionary © HarperCollins Publishers::

time capsule noun

1. a container holding articles, documents, etc, representative of the current age, buried in the earth or in the foundations of a new building for discovery in the future