The Hebrew word יש yesh has a number of meanings. According to Milon Morfix it can mean:
there is, there are ; one must, it is necessary to ; one may, it may; some, sometimes, it may be that
However, it can also mean "got it! did it!". This meaning is used as an exclamation following a success. From where did this expression originate? Rosenthal says it was influenced by the English phrase, of similar meaning - "Yes!" (And, no, the English word yes did not derive from the Hebrew yesh.)
Since the meaning of the two are so similar, it makes you wonder why the Israeli satellite television provider couldn't use a Hebrew name and call themselves Yesh!