What does "pay down" mean?

To partially repay (a loan or, metonymically, the thing financed by it).

What is a synonym for "pay down"?

Common synonyms include: amortise, amortized, amortizes.

verb

verb ·Rare ·Advanced level

Verb

1
To partially repay (a loan or, metonymically, the thing financed by it). transitive
"He paid down his loan for the first five months."

"He paid down his loan for the first five months."