To be an item

To be an item - if two people are an item, they are having a romantic relationship.

Example - "I saw Darren and Emma there. Are they an item?"

Image - http://www.azquotes.com/picture-quotes/quote-marilyn-and-i-were-rumored-to-be-an-item-we-were-friends-nothing-more-marilyn-was-one-sammy-davis-7-37-20.jpg