# tuff

/ˈtəf/ (US) · /tˈʌf/ (UK) · CEFR C1 · Noun

Source: https://englishreference.com/word/tuff
Updated: 2026-05-18

## Definition

a type of rock made of volcanic ash that has been pressed together over a long time. It is usually soft and has a rough, grainy texture.

For teachers: a rock formed by the consolidation of volcanic ash or other pyroclastic material. It is typically a fine-grained, porous sedimentary rock that is relatively soft and easily eroded.

## Examples

- The cliffs are made of dark grey tuff.
- Archaeologists found ancient tools buried in layers of tuff, which helped them date the site accurately.
- The geological survey noted that the tuff layer was highly porous, making it an excellent aquifer for the local community but a poor foundation for heavy structures.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.