A Peter Pan collar is a specific type of shirt collar, usually found on women's and girl's clothing. The shape and name of the Peter Pan collar appear to have originated in the mid-twentieth century. The design became very popular for school uniforms, and began to spill over into popular culture. Despite being named after a masculine character, the Peter Pan collar is associated primarily with feminine wear, and rarely appears in men's fashion.
Credit: Wise Geek
Sources: Collectoratorone, Devon Smith, Annabelle Rose, Carl's Old Photos,