What Exactly Qualifies to Be a Bikini Bridge?

Curious about what exactly qualifies to be a bikini bridge? I suppose the unofficial definition--the made-up term has no official definition to date--is the following: Bikini bridges are when "bikini bottoms are suspended between the two hip bones, causing a space between the bikini and the lower abdomen." Translation: It's when a woman is so lean that a bikini bottom rests on a woman's portruding hip bones and creates a gap between the fabric and her abdomen   This all sounds really good to me, so I picked some 'selfie' examples from the twitter site @ATeenyBikini.  The last pic isn't really a 'bikini bridge', but it's hot so I posted it anyway!