In the Thai language, this means rice, but it's one of those pesky words with tones, so if you don't say it right, you could be saying some other word - in this case, white or he. Hmm. No way to guide you here in the correct pronounciation; sorry.
There are two main types of rice grown and consumed in Thailand: jasmine rice and sticky rice. The former is called either khao plao, plain rice, or more poetically, khao suay, beautiful rice, while the latter is referred to as khao neow, neow meaning sticky.
The word for "eat" in Thai is kin or gin (unaspirated k sound), but this word is rarely used alone. Usually you either kin khao, eat rice - that is, eat a meal which has rice as the staple - or kin len, literally play eat, or snack. The Thai are inveterate snackers, consuming vast quantities of fried bananas; grilled squid; fresh fruit sprinkled with salt, sugar, and chili; and a thousand other morsels sold by street vendors throughout the kingdom. The Thai seem to be able to snack constantly without gaining an ounce. Farang are less fortunate in this regard, as I can tell you from experience: those fried bananas add up quite quickly!
A standard way to greet a friend while you are eating is Kin khao roo yang, Have you eaten (rice) yet?, to which the usual reply is kin laew, I already ate.
Khao San Road, by the way, contains the word for rice, plus san or sahn, meaning raw or unthreshed.