On to today's root, which is ربع or r-b-ayn (there's no equivilant letter in English for this one) and is pronounced something like "raba'a." The basic root means "to sit" or "to stay, live" and other forms of the verb mean "to quadruple" or "to sit cross-legged." That form II meaning of quadrupling results in nouns meaning "four," "quarter" (both as 1/4 and a delineated physical area), and "square," plus lots of related nouns. When you talk about the Empty Quarter in Saudi Arabia, the name uses this root, for example, and you also use it in math all the time, obviously.
In Arabic a few weeks ago, we were talking about women who have been political leaders and this root came up again. The form V verb "taraba'a" means to sit cross-legged, but if it's used in a phrase with the word throne, it would be translated as "to ascend the throne." The other woman in my class is also an American and both of us were having a hard time figuring out what our teacher was trying to tell us that connected sitting cross-legged and thrones, because in English, one never would sit cross-legged on a throne, especially in the context of becoming a queen or king. I love seeing a little piece of cultural differences like this.