Certainly; most likely; truly; probably. Z () Z, the twenty-sixth and last letter of the English alphabet, is a vocal consonant. It is taken from the Latin letter Z, which came from the Greek alphabet, this having it from a Semitic source. The ultimate origin is probably Egyptian. Etymologically, it is most closely related to s, y, and j; as in glass, glaze; E. yoke, Gr. /, L. yugum; E. zealous, jealous. See Guide to Pronunciation, // 273, 274.