An "arch pic" is a term used to describe a photo or short video where the subject forms an arch with their body. This is often used to showcase flexibility, athleticism, or to accentuate ones curves or physique. The term "arch pic day" is also used on June 4th as a day where someone's significant other is expected to send an "arch pic" and it is allowed if they ask for one back. However, it's important to note that "arch snap" is a term used to describe a Snapchat picture that guys ask girls to send, which is technically like a nude but more enjoyable than a titty pic.