Which type of nail color does not dry but cures under a UV or LED lamp?

Gel polish is specifically formulated to be cured under UV or LED light, which distinguishes it from traditional nail polish. When gel polish is applied, it remains in a liquid state until it is exposed to the specific wavelength of light emitted by these lamps. The curing process causes the gel to harden and adhere firmly to the nail, providing a long-lasting and durable finish.

In contrast, base coats, topcoats, and traditional polish do not require this curing process. Base coats and topcoats are typically used to enhance the adhesion of the nail polish and protect the nails but dry through evaporation of solvents in the air rather than through UV or LED light. Traditional nail polish also dries via evaporation, which is a much quicker and simpler process but does not offer the same durability as gel polish.

Thus, gel polish is unique in its curing requirement, setting it apart as the correct choice in this question.