You can count on Welsh-derived words to provide terms with consonants in interesting strings and no pronunciation like standard English. “Cwm,” meaning “a steep-walled basin found on the side of a mountain,” is pronounced “kum,” with the vowel sounding like the “oo” in “book.” What’s called a cwm in Wales is called a cirque elsewhere. These deep basins are mostly created by glacial erosion, and they often contain a small lake. The Welsh word is believed to have come from the Greek “kymbē,” meaning “drinking cup.”