The original version of this slogan was "Rah Rah, Jayhawk, KU" put forward by E. H.S Bailey, a chemistry professor, at 1886, which was repeated three times. At first, it was used as the cheering slogan of the chemistry student union in the competition. Later, it spread all over the campus of the University of Kansas. Later, Rah was replaced by rock chalk, which came from chalk (chalk, a limestone produced in the seat of the University of Kansas).
The slogan of rock chalk is very famous in the United States. Ted Roosevelt, the 26th president of the United States, thinks it is the best university slogan he has ever heard. 1920 Belgian Olympic games, the king of Belgium asked the United States team, what is the typical university slogan in the United States? American athletes who graduated from different universities in the United States agreed that this was the rock chalk slogan of the University of Kansas.
Today, in some large-scale school activities (sports competition is the most typical representative), school teachers and students often shout these two words together. Many professors and even principals like to end their speeches with rock chalk. The slogan itself has no practical significance (please don't translate it into rock chalk ...), just because the English word rhymes at the end and is shouted out with great momentum, it has become the slogan of the University of Kansas.
Incidentally, during his visit to the University of Kansas on October 25th, 20 15, President Obama greeted the audience with rock chalk before his speech.