What does "black catechu" mean?

extract of the heartwood of Acacia catechu used for dyeing and tanning and preserving fishnets and sails; formerly used medicinally

What is a synonym for "black catechu"?

Common synonyms include: catechu.

Rare ·Advanced level

Noun

1
extract of the heartwood of Acacia catechu used for dyeing and tanning and preserving fishnets and sails; formerly used medicinally wordnet