ravine
峪 centers on a deep, narrow valley between mountains: a ravine.
峪 combines 山 (mountain) and 谷 (valley), directly depicting a mountain valley or ravine. The exact historical development is uncertain, but the semantic combination is straightforward.
A mountain 山 beside a valley 谷 forms a deep ravine between the peaks.
For ヨク, imagine a yoke of oxen struggling through a narrow ravine: yoke -> ヨク, and the ravine squeezes them between the mountains.