This is the 2683rd most frequent Japanese word.
渡る
"渡る" means "to cross" or "to go across."
In this sentence, 渡る (to cross) is used to indicate the action of moving over a bridge from one side to the other.
橋を渡る。
I cross the bridge.
Here, 渡る is used to describe the action of spending or moving through a season, such as winter.
冬を渡る鳥が南へ向かう。
The birds that pass through the winter head south.
In this case, 渡る metaphorically represents embarking on or transitioning into a new stage or journey in life.