Hip dips are indentations on the outer middle of the hips, between the upper and lower pelvic bone. They are also called "violin hips," for the distinctive shape they form.

Not to be confused with:

• visible upper pelvic bone
• crotch lines

Trivia

"Hip dips are entirely caused by genetics and the shape of your pelvis. When someone has hip dips, this means that their hip bone is located higher than their femur, which causes their muscles and fat to curve inwards." (Source: https://www.byrdie.com/hip-dips-instagram-trend)