This is the 4839th most frequent Japanese word.
渡り
"渡り" means "crossing" or "migration."
Here, '渡り' is used as a noun referring to the act or process of crossing, in this example, a river.
彼は川の渡りを手伝いました。
He helped with the crossing of the river.
In this sentence, '渡り' is part of the compound '渡り鳥', which refers to 'migratory birds'. The word '渡り' implies movement or migration.
渡り鳥が南へ向かっています。
Migratory birds are heading south.
Here, '渡り' is used in the compound '渡り廊下', which refers to a 'connecting corridor' or 'walkway'. The usage implies a passageway for transit.