Zipper, zealot, zombie and zephyr are some six-letter words that use the letter "Z." The definition of zealot is a person who is excessive or fanatical; this word has its origins in the Greek "zelotes." A zombie is a corpse or previously dead person who has come back to life.
These undead creatures are often in horror and fantasy movies like "Dawn of the Dead," "Night of the Living Dead," and "Zombieland."
A zephyr is a gentle breeze or lightweight clothing. The word zephyr is also part of the title of a song by Red Hot Chili Peppers called, "The Zephyr Song."