Other forms: breaking new ground; broke new ground; breaks new ground
If you've ever discovered something or done something nobody else has done, you managed to break new ground. This refers to making advancements or innovations.
To break new ground means to make a discovery or innovation. That might be anything from discovering a new medical treatment, to inventing a new genre of fiction, or pushing for new legal protections. While it's similar to the phrase break ground, and both come from literally breaking ground by digging (specifically, plowing a field that had never been farmed before), the two phrases are almost always distinct. Break ground means to start a new project, whereas break new ground means to innovate, or pioneer a new frontier or idea.