The probability that the occurance of certain words, such as in a text, starts high, then tapers off. In the English language, for example, words like “and,” “of,” “the” and “to” occur frequently, while words like “indistinguishable” occur rarely.

In layman’s terms, Zipf’s Law is a sort of mathematical representation for “the 80/20 rule” (but we’ll spare you the actual equation.) Named for Harvard linguistics professor George Kingsley Zipf, who collected his observations in a book titled “Human Behavior and the Principle of Least Effort.”

Zipf’s Law entered the cable technical lexicon in 2004, when technologists involved in testing switched broadcast video applied the law to video viewing patterns.