Literally 'cloud fir' —
云 (cloud) +
杉 (fir/cedar). The name evokes the tree's habit of growing tall in mountain mist. Don't confuse with
松 (sōng, pine) or
柏 (bǎi, cypress) — Chinese distinguishes conifers carefully:
松/
柏/
杉 are all in the casual category 'evergreen trees' but botanically distinct.