This is the 3939th most frequent Russian word.
дно
The bottom or the base (of something).
In this sentence, 'дно' relates to the bottom part or base of an object, specifically a pot.
Кастрюля упала на пол и вмяла своё дно.
The pot fell to the floor and dented its bottom.
Here, 'дно' is used metaphorically to describe the lowest or worst point of a situation, in this case, a financial one.
Он достиг дна в финансовом плане и решил начать всё сначала.
He hit rock bottom financially and decided to start over.
Here, the word 'дно' refers to the bottom surface of a sea or body of water.