source: http://beginnersinvest.about.com/
You probably heard this already specially if you are playing in casinos but for newbie stock investors I got this definition from Wikipedia:
The phrase was coined by Oliver Gingold of Dow Jones sometime in 1923 or 1924. Company folklore recounts that the term apparently got its start when Gingold was standing by the stock ticker at the brokerage firm that later became Merrill Lynch. Noticing several trades at USD$200 or USD$250 a share or more, he said to Lucien Hooper of W.E. Hutton & Co. that he intended to return to the office to “write about these blue chip stocks.” Thus the phrase was born. It has been in use ever since, originally in reference to high-priced stocks, more commonly used today to refer to high-quality stocks. In contemporary media, Blue Chips and their daily performances are frequently mentioned alongside other economic averages like the Dow Jones Industrial Average.
There is no specific criteria or standard that is generally followed but I got this guidelines from EconomyWatch
1. Revenues: Companies with revenues higher than that generated
by industry peers.
2. Earnings: Companies that have been generating healthy earnings
on a consistent basis.