What does "depthen" mean?

To increase the depth of; make deep or deeper

What is a synonym for "depthen"?

Common synonyms include: deepen.

verb

verb ·Rare ·Advanced level

Verb

1
To increase the depth of; make deep or deeper archaic, transitive
"And in 1770, a Mr. John Gayford went to Holland to buy an engine to depthen the haven."

"And in 1770, a Mr. John Gayford went to Holland to buy an engine to depthen the haven."

From depth + -en.