twin sister

One of two sisters born at the same birth, or the girl when the twins are of different sexes. twin-spot carpet, s. Entom.: A European geometer moth, Larentia didymata. The fore wings brown, with four irregular, transverse waved pale-gray bars, with a double dark spot (whence the name) between the third and fourth bars. The caterpillar feeds on Anthriscus sylvestris. ( Newman .)