The works of Ādi Śaṅkarācārya

Viṣṇusahasranāmastotram

Verse 487

अचलः ।वायुरूपेण चलतीति चलः ॥

In plain words

Acala: the Unmoving. And Cala — because he moves as the wind moves; that is what the name says.

Close to the Sanskrit

Acala (the Unmoving). In the form of wind he moves — thus, Cala (the Moving).