The walnut is a rounded or ovoid fruit, according to the variety, with a hard and wrinkled shell or mesocarp of reddish-brown colour, that is formed by two valves, divided in two or four sections that contain the kernels or endocarps, of irregular shape, light yellowish colour and covered with a thin brown skin.

The walnut is a rounded or ovoid fruit, according to the variety, with a hard and wrinkled shell or mesocarp of reddish-brown colour, that is formed by two valves, divided in two or four sections that contain the kernels or endocarps, of irregular shape, light yellowish colour and covered with a thin brown skin.