Acronym for 'Eyebrow Raise'. Usually used when someone finds something so intriguing, befuddling, interesting, no words can do it justice. The raise of a single eyebrow alerts any onlooker that further explanation is needed; often followed with disapproval and shame directed at the onlooker.
Jess on Meghan's wall:
it's been too long since we've been filthy and creepy
Aimee befuddled by this post stared at her computer with a raised eyebrow...