sea

In Old English, sæ was a wonderfully broad word: it could describe the ocean, a lake, a pool, a marsh, or even the Bristol Channel. Germanic speakers apparently did not always draw the modern line between “sea” and “lake”; German See still means “sea” when feminine and “lake” when masculine. The word’s ultimate ancestry is uncertain: one proposal connects it with Proto-Indo-European *sh₂ey-wo-, associated with fierceness or affliction, while another links it to *seykʷ-, “to percolate” or “filter”—perhaps water understood as something that seeps and moves. By the 1660s, astronomers were calling the Moon’s dark patches seas, or maria, because telescopes had not yet revealed that those vast gray plains were dry rock. And when Shakespeare wrote of a “sea change” in The Tempest around 1610, the ocean began lending its power to transformation itself: a sea is not merely water, but a force that remakes whatever it touches.