9-letter words containing r, e, b, i, t
- ytterbium — a rare metallic element found in gadolinite and forming compounds resembling those of yttrium. Symbol: Yb; atomic weight: 173.04; atomic number: 70; specific gravity: 6.96.
- zeitgeber — an environmental cue, as the length of daylight or the degree of temperature, that helps to regulate the cycles of an organism's biological clock.