D, fourth letter in the alphabets derived from Greek and Latin. It originated in an Egyptian hieroglyph that represented a hand. When adopted by the Phoenicians, this sign was called daleth (“door”) from its resemblance to the aperture of a tent. The resemblance may be traced in the Greek letter Δ, the name of which, delta, was derived from daleth. In English, the sound of d is the voiced alveolar stop (see Phonetics).