The word “relevant,” I was recently surprised to discover, shares an etymology with the word “relieve.” This seems obvious enough once you know it—only a few letters separate the words—but their usages diverged so long ago that I had never associated them before. Searching out etymologies is an old habit, picked up in the decades when I aspired to be a poet. Language is fossil poetry, Emerson says, and the poem the Oxford English Dictionary lays out in this case is remarkably moving. The common forebear of both “relevant” and “relieve” is the French relever, which meant, originally, to…