Though you might not think so, there are many different words allowed by Scrabble... zabaoine, zabajone, zacaton, zaddick, zaddik, zaffar, zaffer, zaffir, zaffre, zaftig, zag, zaibatsu, zaikai, zaire, zamarra, zamarro, zamia, zamindar, zanana, zander, zanier, zanies, zaniness, zany, zanyish, zanza, zap, zapateo, zapper, zappy, zaptieh, zaratite, zareba, zareeba, zarf, zariba, zarzuela, zastruga, zax, zayin, zazen, zeal, zealot, zealotry, zealous, zeatin, zebec, zebeck, zebra, zebrass, zebrine, zebrond, zebu, zecchin, zecchino, zechin, zed, zedoary, zee, zein, zek, zelkova, zemindar, zemstvo, zenaida, zenana, zenith, zenithal, zeolite, zephyr, zeppelin, zero, zeroth, zest, zestful, zesty, zeta, zeugma, zibeline, zibet, zibeth, zig, ziggurat, zigzag, zikkurat, zikurat, zilch, zill, zillah, zillion, zinc, zincate, zincic, zincify, zincite, zincked, zincking, zincky, zincoid, zincous, zincy, zineb, zing, zingana, zingaro, zinger, zingy, zinkify, zinky, zinnia, zip, zipless, zipper, zipping, zippy, ziram, zircon, zirconia, zirconic, zit, zither, zithern, ziti, zizit, zizith, zizzle, zloty, zoa, zoarium, zodiac, zoea, zoftig, zoic, zoisite, zombi, zombie, zombiism, zonal, zonary, zonate, zonation, zone, zoneless, zoner, zonetime, zoning, zonk, zonula, zonule, zoo, zoochore, zoogenic, zooglea, zoogloea, zooid, zooks, zoolater, zoolatry, zoology, zoom, zoomania, zoometry, zoomorph, zoon, zoonoisis, zoophile, zoophily, zoophobe, zoophyte, zoosperm, zoospore, zootomy, zori, zoril, zorilla, zorille, zorillo, zoster, zounds, zowie, zoysia, zucchini, zwieback, zydeco, zygoid, zygoma, zygosis, zygosity, zygote, zygotene, zymase, zyme, zymogen, zymogene, zymogram, zymology, zymosan, zymosis, zymurgy, and zyzzyva. That's every single one of them.
EDIT: The above list is outdated and limited to 8 letter words. You should also include the following words.
ZA
ZABAGLIONE
ZABAGLIONES
ZABAIONES
ZABAJONES
ZACATONS
ZADDIKIM
ZAFFARS
ZAFFERS
ZAFFIRS
ZAFFRES
ZAGGED
ZAGGING
ZAGS
ZAIKAIS
ZAIRES
ZAMARRAS
ZAMARROS
ZAMIAS
ZAMINDARI
ZAMINDARIS
ZAMINDARS
ZANANAS
ZANDERS
ZANIEST
ZANILY
ZANINESSES
ZANZAS
ZAP
ZAPATEADO
ZAPATEADOS
ZAPATEOS
ZAPPED
ZAPPERS
ZAPPIER
ZAPPIEST
ZAPPING
ZAPS
ZAPTIAH
ZAPTIAHS
ZAPTIEHS
ZARATITES
ZAREBAS
ZAREEBAS
ZARFS
ZARIBAS
ZARZUELAS
ZAS
ZASTRUGI
ZAXES
ZAYINS
ZAZENS
ZEALOTRIES
ZEALOTS
ZEALOUSLY
ZEALOUSNESS
ZEALOUSNESSES
ZEALS
ZEATINS
ZEBECKS
ZEBECS
ZEBRAFISH
ZEBRAFISHES
ZEBRAIC
ZEBRANO
ZEBRANOS
ZEBRAS
ZEBRASSES
ZEBRAWOOD
ZEBRAWOODS
ZEBRINES
ZEBROID
ZEBUS
ZECCHINI
ZECCHINOS
ZECCHINS
ZECHINS
ZED
ZEDOARIES
ZEDS
ZEES
ZEINS
ZEITGEBER
ZEITGEBERS
ZEITGEIST
ZEITGEISTS
ZEKS
ZELKOVAS
ZEMINDARIES
ZEMINDARS
ZEMINDARY
ZEMSTVA
ZEMSTVOS
ZENAIDAS
ZENANAS
ZENITHS
ZEOLITES
ZEOLITIC
ZEP
ZEPHYRS
ZEPPELINS
ZEPPOLE
ZEPPOLES
ZEPPOLI
ZEPS
ZEPTOSECOND
ZEPTOSECONDS
ZERK
ZERKS
ZEROED
ZEROES
ZEROING
ZEROS
ZESTED
ZESTER
ZESTERS
ZESTFULLY
ZESTFULNESS
ZESTFULNESSES
ZESTIER
ZESTIEST
ZESTILY
ZESTING
ZESTLESS
ZESTS
ZETAS
ZETTABYTE
ZETTABYTES
ZEUGMAS
ZEUGMATIC
ZIBELINES
ZIBELLINE
ZIBELLINES
ZIBETHS
ZIBETS
ZIDOVUDINE
ZIDOVUDINES
ZIGGED
ZIGGING
ZIGGURATS
ZIGS
ZIGZAGGED
ZIGZAGGER
ZIGZAGGERS
ZIGZAGGING
ZIGZAGGY
ZIGZAGS
ZIKKURATS
ZIKURATS
ZILCHES
ZILLAHS
ZILLIONAIRE
ZILLIONAIRES
ZILLIONS
ZILLIONTH
ZILLS
ZIN
ZINCATES
ZINCED
ZINCIFIED
ZINCIFIES
ZINCIFYING
ZINCING
ZINCITES
ZINCS
ZINE
ZINEBS
ZINES
ZINFANDEL
ZINFANDELS
ZINGANI
ZINGANO
ZINGARA
ZINGARE
ZINGARI
ZINGARO
ZINGED
ZINGERS
ZINGIER
ZINGIEST
ZINGING
ZINGS
ZINKENITE
ZINKENITES
ZINKIFIED
ZINKIFIES
ZINKIFYING
ZINNIAS
ZINS
ZIPLOCK
ZIPPED
ZIPPERED
ZIPPERING
ZIPPERS
ZIPPIEST
ZIPPING
ZIPS
ZIRAMS
ZIRCALOY
ZIRCALOYS
ZIRCONIAS
ZIRCONIUM
ZIRCONIUMS
ZIRCONS
ZITHERIST
ZITHERISTS
ZITHERNS
ZITHERS
ZITIS
ZITS
ZIZZLED
ZIZZLES
ZIZZLING
ZLOTE
ZLOTIES
ZLOTYCH
ZLOTYS
ZOANTHARIAN
ZOANTHARIANS
ZOARIA
ZOARIAL
ZOCALO
ZOCALOS
ZODIACAL
ZODIACS
ZOEAE
ZOEAL
ZOEAS
ZOECIA
ZOECIUM
ZOISITES
ZOMBIELIKE
ZOMBIFICATION
ZOMBIFICATIONS
ZOMBIFIED
ZOMBIFIES
ZOMBIFY
ZOMBIFYING
ZOMBIISMS
ZOMBIS
ZONA
ZONAE
ZONALLY
ZONATE
ZONATED
ZONATIONS
ZONED
ZONERS
ZONES
ZONETIMES
ZONKED
ZONKING
ZONKS
ZONULAE
ZONULAR
ZONULAS
ZONULES
ZOOCHORES
ZOOECIA
ZOOECIUM
ZOOEY
ZOOGAMETE
ZOOGAMETES
ZOOGENIES
ZOOGENOUS
ZOOGENY
ZOOGEOGRAPHER
ZOOGEOGRAPHERS
ZOOGEOGRAPHIC
ZOOGEOGRAPHICAL
ZOOGEOGRAPHIES
ZOOGEOGRAPHY
ZOOGLEAE
ZOOGLEAL
ZOOGLEAS
ZOOGLOEAE
ZOOGLOEAL
ZOOGLOEAS
ZOOGLOEIC
ZOOGRAPHIES
ZOOGRAPHY
ZOOIDAL
ZOOIDS
ZOOIER
ZOOIEST
ZOOKEEPER
ZOOKEEPERS
ZOOLATERS
ZOOLATRIES
ZOOLOGIC
ZOOLOGICAL
ZOOLOGICALLY
ZOOLOGIES
ZOOLOGIST
ZOOLOGISTS
ZOOMANIAS
ZOOMED
ZOOMETRIC
ZOOMETRIES
ZOOMING
ZOOMORPHIC
ZOOMORPHS
ZOOMS
ZOONAL
ZOONED
ZOONING
ZOONOSES
ZOONOSIS
ZOONOTIC
ZOONS
ZOOPHILES
ZOOPHILIA
ZOOPHILIAS
ZOOPHILIC
ZOOPHILIES
ZOOPHILOUS
ZOOPHOBES
ZOOPHOBIA
ZOOPHOBIAS
ZOOPHYTES
ZOOPHYTIC
ZOOPLANKTER
ZOOPLANKTERS
ZOOPLANKTON
ZOOPLANKTONIC
ZOOPLANKTONS
ZOOS
ZOOSPERMS
ZOOSPORANGIA
ZOOSPORANGIUM
ZOOSPORES
ZOOSPORIC
ZOOSTEROL
ZOOSTEROLS
ZOOTECHNICAL
ZOOTECHNICS
ZOOTIER
ZOOTIEST
ZOOTOMIC
ZOOTOMIES
ZOOTOMIST
ZOOTOMISTS
ZOOTY
ZOOXANTHELLA
ZOOXANTHELLAE
ZORILLAS
ZORILLES
ZORILLOS
ZORILS
ZORIS
ZOSTERS
ZOUAVE
ZOUAVES
ZOUK
ZOUKS
ZOYSIAS
ZUCCHETTI
ZUCCHETTO
ZUCCHETTOS
ZUCCHINIS
ZUGZWANG
ZUGZWANGS
ZUZ
ZUZIM
ZWIEBACKS
ZWITTERION
ZWITTERIONIC
ZWITTERIONS
ZYDECOS
ZYGAPOPHYSES
ZYGAPOPHYSIS
ZYGODACTYL
ZYGODACTYLOUS
ZYGOMAS
ZYGOMATA
ZYGOMATIC
ZYGOMATICS
ZYGOMORPHIC
ZYGOMORPHIES
ZYGOMORPHY
ZYGOSE
ZYGOSES
ZYGOSITIES
ZYGOSPORE
ZYGOSPORES
ZYGOTENES
ZYGOTES
ZYGOTIC
ZYMASES
ZYMES
ZYMOGENES
ZYMOGENIC
ZYMOGENS
ZYMOGRAMS
ZYMOLOGIC
ZYMOLOGIES
ZYMOLYSES
ZYMOLYSIS
ZYMOLYTIC
ZYMOMETER
ZYMOMETERS
ZYMOSANS
ZYMOSES
ZYMOTIC
ZYMURGIES
ZYZZYVAS
ZZZ
EDIT: These typos are in the original list:
ZEBROND is not a word, should be ZEBROID
ZINGANA is not a word, should be ZINGARA
ZINGARO is not a word, should be ZINGANO
ZOONOISIS is not a word, should be ZOONOSIS
Some scrabble words that end with Z are:adzblintzblitzbuzzchintzditzfezfizzfrizzfuzzglitzjazzkibbutzpizazzquartzquizRitztopazwaltzwhiz
Yup, it sure is. The only two 2-letter words starting with Z are ZA (short for pizza) and ZO. =)
zygote
Some four letter words that start with Z are:zanyzealzebu (domesticated ox)zerozestzetazinczingzitizonezonkzoom
There are no words that contain a Z that also end in J
Some scrabble words that end with Z are:adzblintzblitzbuzzchintzditzfezfizzfrizzfuzzglitzjazzkibbutzpizazzquartzquizRitztopazwaltzwhiz
Words that have z and y include:dizzyfrizzygrizzlyhazyjazzylazyritzytizzy
There are no Scrabble words that end with FZ.
blazecozycrazecrazydazedozefreezefrozegazeglazegrazehazelazelazymazeplazaprizerazesizeunzipzipzoo
zoology
ZLECK
Yup, it sure is. The only two 2-letter words starting with Z are ZA (short for pizza) and ZO. =)
ZebraBezzazzBizarreBedazzleBuzzBlizzardBuzzardBaptizeBulldozerBrazenBlitzBronze
Zillionaire, zombie and zone are words. They begin with Z and end with E.
Some two-letter words starting with "V" include: Ve Vin Vex
zeal
enzyme