1. One of the two halves of bilaterally symmetrical animals; one of any opposite symmetrical or homotypic parts in animals and plants

Derived forms: antimeres

• order Thymelaeales
• order Thysanoptera
• order Thysanura
• order Tinamiformes
• order Torpediniformes
• order Tremellales
• order Trichoptera
• order Trogoniformes
• order Tuberales
• order Tubulidentata
• order Tulostomatales
• order Ulvales
• order Umbellales
• order Uredinales
• order Urodella
• order Uropygi
• order Urticales
• order Ustilaginales
• order Volvocales
• order Xiphosura
• order Xyridales
• order Zeomorphi
• order Zygnemales
• order Zygnematales
• order-Chenopodiales