This is the 2732nd most frequent Japanese word.
結ん
"結ん" is the conjugated form of "結ぶ" (musubu), meaning "to tie" or "to connect."
Here, '結んだ' (musunda) is used to mean 'signed' or 'formed' in the context of creating an agreement.
契約を結んだ。
I signed a contract.
'結んだ' (musunda) in this sentence refers to the act of tying something, specifically shoelaces in this case.
私は靴紐を結んだ。
I tied my shoelaces.
In this context, '結ぶ' (musubu) implies forming or establishing a connection or relationship, like friendships.