What does 3 DNA segments mean?

When you compare multiple DNA Matches, you might encounter triangulated segments: segments of DNA that all 3 (or more) of you have in common. If you have a triangulated segment with a known relative and a mystery DNA Match, that means that all of you likely share a common ancestor.

What does a DNA match really mean?

Simply put, a DNA match is an individual that shares some portions of their genetic composition with you. DNA companies use member matching to identify other members from their database that are related to you.