Part of Speech: Noun

Definition: Either one of two things that are closely connected or correlated with each other

Source: http://www.merriam-webster.com/dictionary/correlate?show=0&t=1387344231

Encountered: In the article “The Happiest and Saddest Places in New York City, According to Twitter” by Brian Merchant. “Elsewhere, for the most part, happiness tends correlate to leisure and wealth, though perhaps not as overtly as you’d guess.”

Understanding: Now I understand that he is saying happiness is related to leisure and wealth.