This is an extreme level of pedantry(forgive me), but there is a subtle difference between "DC" and "할인" (and also "세일"). "할인" refers to a wide variety of disc

This is an extreme level of pedantry(forgive me), but there is a subtle difference between "DC" and "할인" (and also "세일"). "할인" refers to a wide variety of discounts: it may have a few conditions (minimum quantity, membership, etc.), be available only for a certain period of time, or be a fixed amount or percentage. "세일" is pretty much the same, although it puts a tiny bit more focus on being a limited-time offer and being percentage-based. "DC" almost always refers only to a simple, percentage-based discount or rounding down the price. It also sounds much more spontaneous and less formal.