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.