Put the meaning into your own words.

Take a moment before opening the definition. There is no timer and no penalty for needing another look.

CARD 1 OF 1

keystone

noun

Reveal meaning and examples

The wedge at the top of an arch that holds its other pieces in position.

The mason trimmed the keystone until the two sides of the arch held firm.

Dictionary practice example.

The arch lacked its final keystone, so the builders kept the temporary supports in place.