It is one of the individual female reproductive organs in a flower.
A carpal is composed of an ovary, a style and a stigma, although someflowers have carpets without a distinct style.
in origins carpels are leaves that have evolved to enclose ovules.
the word listil is sometime used to refer to a single carpel or to several carpels fused together.
1)*The female part of the flower is referred to either as the carpel or the pistil.OR
*A carpel is one of the ovule-bearing structures in an angiosperm that comprises the innermost whorl of a flower.
2)Carpels are thought to be derived from ovule-bearing leaves or leaf homologues (megasporophyll), which evolved to form a closed structure containing the ovules. 
Monocarpous (unicarpellate).
Apocarpous (choricarpous).

Pictures of carpel are attached below,see to it:-.
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