toph

/tɑf/
noun
  1. A type of hard, porous rock formed from volcanic ash, also known as tuff.
    • The ancient buildings were constructed from local toph stone.
    • The cliffs were made of soft toph that eroded easily.
    • Toph is often used in gardening because it drains water well.
Synonyms
What does "toph" mean? | whatsthatwordmean | whatsthatwordmean