"Pin-up girls" refer to models or illustrations that are designed to be attractive and appealing, often used in posters, magazines, and calendars. These images typically feature women in glamorous poses, showcasing fashion and beauty. The term became popular during the 1940s and 1950s, particularly in the context of World War II, when soldiers would keep pictures of these women for inspiration and comfort. The style of pin-up art often emphasizes playful and flirtatious themes, with many images featuring women in vintage clothing or swimwear. Iconic figures like Betty Grable and Marilyn Monroe became symbols of this genre, influencing popular culture and fashion. Today, pin-up art continues to inspire various forms of media, including photography and fashion design.