360 The Realm of Nature 



TALUS, Fr. talus, a slope 



Tangent, L. tango, to touch 



Terrigenous, L. terra, the earth ; geneo, to produce 



Thallophyte, Gr. thallos, a twig ; phuton, a plant 



Thermometer, Gr. therme, heat ; metron, a measure 



Transit, L. trans, across ; eo, to go 



Trias, Gr. trias, union of three 



Trigonometry, Gr. trigonon, triangle ; metron, a measure 



Tropic, Gr. tropos, a turning 



UNIVERSE, L. unus, one ; verto, to turn 



VACUUM, L. vacuum, empty 

 Vermes, L. vermis, a worm 

 Vernal, L. ver, spring 

 Vertebrata, L. vertebra, a joint 

 Vertical, L. vertex, the top 

 Vibration, L. vibro, to quiver 

 Vortex, L. vorto, to turn or whirl 



ZENITH, Arabic, semt-ur-ras, way of the head 

 Zero, Arabic, sifr, nothing (a starting-point) 

 Zone, Gr. zone, a girdle 

 Zoology, Gr. zoon, an animal ; logos, a discourse 



