Polaroids can refer to different things depending on the context. Here are some possible meanings:

• Instant film photograph: A Polaroid picture is an instant film photograph introduced by the Polaroid Corporation in the late 1940s. Polaroid pictures are made inside instant cameras such as Polaroid OneStep+ and Fujifilm Instax Mini 11. The final photograph is always a surprise, and it always looks good even when a novice is behind the lens. The nostalgic film aesthetic gives the photo a nice touch that even the nicest cameras and smartphones can’t quite achieve.
• Polarizing sheet: Polarizing sheets or polarizing filters are commercially known as polaroids. These sheets contain long-chain molecules that are aligned to allow electric field oscillations along only one direction. Polaroids are used to reduce the glare of sunlight in bright settings, to photograph water bodies and objects underwater, and to reduce glare on spectacles and night driving goggles.
• Collectible item: In the context of K-pop, polaroids are one-of-a-kind items since each one is taken by an idol doing a different expression or pose. They are typically very rare and can be obtained through various means such as pre-ordering an album or attending a fan meeting. Polaroids are often collected by fans and can be expensive when resold.

In summary, polaroids can refer to instant film photographs, polarizing sheets, or collectible items depending on the context.