What is the meaning of Sickle?

An implement having a semicircular blade and short handle, used for cutting long grass and cereal crops.

Any of the sickle-shaped middle feathers of the domestic cock.

To cut with a sickle.

To deform (as with a red blood cell) into an abnormal crescent shape.

Of red blood cells: to assume an abnormal crescent shape.

Shaped like the blade of a sickle; crescent-shaped.

Source: wiktionary.org