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.

Example:
What is the order of the the DragonBall Z seasons and the DragonBall Z movies?

Taxonomy
English, dz, Greek, IPA, lowercase, Articles with unsourced statements, Greek zeta, dialects, zed and zee, alphabet, free encyclopedia, capital, Search, Zz, typefaces, dialectal, Latin alphabet, Italian.

Defination from the web:
z as in English and French, or possibly more like /dz/ (as in Italian zeta, zero). The Greek form of Z was a close copy of the Phoenician symbol I, and the Greek inscriptional ... In early Latin, the sound of /z/ developed into /r/ and the symbol became useless. ...