What’s in a number? Should Dow 18K mean anything more than 17,999?

The simple answer is no, but psychologically the former has more weight than the latter.

The Dow Jones index on Tuesday crossed the 18K mark 32 times — back and forth — before settling below.

In an age of high-frequency trading and programmed trading this level should not have a significance. Yet at least on Tuesday it did mean something to the market.

Fed chair Janet Yellen primed the stock market pump on Monday with her walk back of a rate rise this summer. Yet that was not enough to send indices higher.

Let’s see what today brings as dollar is weakening.