The phrase "to pin down" means to identify or determine something with certainty, often by gathering and examining evidence. It can also refer to holding someone in place using physical restraints, such as pins or other sharp objects.
Sentences with «to pin down»
Doing some research and polling each family member about what is important to them in a dog will help pin down what you will be looking for. (humanesocietyofyorkcounty.org)
But researchers could never quite verify the theory because they couldn't pin down exactly what the cost and benefits were or study them over the many generations needed to see evolution in action. (sciencemag.org)
But we'll start today by pinning it down by some simple steps. (thefashionfolks.com)