Cerulean describes things whose blue color resembles the blue of a clear sky.

// The painting depicts leafless trees bordering a cerulean lake.

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“He grins to appease me and reaches into his pocket and pulls out a cerulean fountain pen, marbled and sparkling. It reminds me of the sea on a calm day. ‘It was my grandfather’s,’ he explains. ‘He gave it to me, and now I am giving it to you.’” — Asha Lemmie, The Wildest Sun: A Novel, 2023

There comes a moment in every young crayon user’s life when they graduate from the 8-count (or 16-count, perhaps) box to the treasure trove of 64 glorious sticks of differently colored wax, when they discover that there isn’t just one brown or orange or blue, that when it comes to colors, the sky’s the limit! Such a moment is often the first encounter people have with the word cerulean, a word that slips sibilantly off the tongue like a balmy ocean breeze. Like azure, cerulean describes things whose blue color resembles that of a clear sky; it’s often used in literature (especially travel writing) to paint an enticing image of an even more enticing vista, as in “the cerulean waters of a tropical lagoon.” While azure is thought to hail from the Persian word lāzhuward, with the same meaning, cerulean comes from the Latin adjective caeruleus, meaning “dark blue.” That word most likely comes from caelum, meaning “sky.”