The term "common thread" refers to a shared characteristic, interest or experience that connects two or more things. It is something that runs through different elements and brings them together in some way. This could be a theme, idea, goal, emotion, personality trait, etc., that links various aspects of life, events, situations, people, objects, etc. The phrase "common thread" suggests that there is an underlying connection between the things being referred to, which can help to make sense of them or bring clarity to a complex situation.