As nouns the difference between ovule and carpel

is that ovule is the structure in a plant that develops into a seed after fertilization; the megasporangium of a seed plant with its enclosing integuments while carpel is one of the individual female reproductive organs in a flower. A carpel is composed of an ovary, a style, and a stigma, although some flowers have carpels without a distinct style. In origin, carpels are leaves (megasporophylls) that have evolved to enclose the ovules. The term pistil is sometimes used to refer to a single carpel or to several carpels fused together.