log; unsawn timber
Refers to a whole, unsawn log, often used in contexts like log houses or log bridges.
They floated logs down the river to transport them.
この橋は丸木でできている。
This bridge is made of logs.
log bridge
dugout canoe
Compound of 丸 (まる, 'round') and 木 (き, 'tree, wood'), literally 'round wood'.