1. Coming next after the twenty-ninth in position
   - thirtieth

See also: ordinal

• genus Xylopia
• genus Xylosma
• genus Xyphophorus
• genus Xyris
• genus Yucca
• genus Zaglossus
• genus Zalophus
• genus Zamia
• genus Zannichellia
• genus Zantedeschia
• genus Zanthoxylum
• genus Zapus
• genus Zea
• genus Zenaidura
• genus Zerumbet
• genus Zeus
• genus Zigadenus
• genus Zingiber
• epidermoid
• epidiascope
• epididymis
• epididymitis
• epidote
• epidural
• epidural anaesthesia