Other forms: voces populi
In Latin, vox populi literally means "voice of the people," so use this phrase to refer to an idea or opinion that most people share.
You can use this phrase to talk about the general consensus or popular sentiment, like the vox populi in your town that complains about potholes in the roads or the vox populi at school hoping for a snow day. In journalism, a series of quick interviews with random people on the street is also known as a vox populi; in fact, this is how the phrase is used most often these days, although it's usually shortened to vox pop.