- xxix
- xxviii
- XXXI
- xxx
- xxvi
- XXXIV
- XXXVII
- XXXIII
- XXXVI
- XXXVIII
- xxy
- xxy_syndrome
- xy
- xylanthrax
- xylariaceae
- xylaria mali
- xylocarp
- xyle
- xylem
- xylaria polymorpha
- xylene
- xylocopa
- xylocaine
- xylocrap
- xylographical
- xylographic
- xylomelum pyriforme
- xylology
- xylopia aethiopica
- xylosma congestum
- xyridaceae
- xyster
- xyy
- xyris
- xyphophorus
- xenogamy
- xenon
- xenopodidae
- xenorhyncus
- xenosauridae
- xerobates
- xerocollyrium
- xxiii
- XXXV
- xylaria
- xylograph
- xylography
- xylophone
- xylopia
- xyphophorus helleri