A type of volcanic ash used for mortar or for cement that sets under water.
- ‘The Romans invented concrete, mixed from pozzolana, a volcanic ash mined on the slopes of Mount Vesuvius, which forms a natural cement when combined with lime.’
- ‘It included seawater, lime and sand (pozzolana) and chunks of volcanic rock from the Bay of Naples - the same source for material used in ancient construction efforts at Caesarea and elsewhere in the region.’
- ‘The ashes have been potential pozzolanic materials suitable for use in lime - pozzolana mixes and for Portland cements replacement.’
Early 18th century: from Italian, from pozz(u)olana ‘(earth) of Pozzuoli’, a town near Naples.
We take a look at several popular, though confusing, punctuation marks.