The pomegranate is a shrub or small tree growing 1.5 to 5 m (5 to 16 ft) high, with multiple spiny branches.^[5] It is long-lived, with some specimens in France surviving for 200 years.^[6] The leaves are opposite or subopposite, glossy, narrow oblong, entire, 1.9–5 cm (0.7–2.0 in) long, and 0.8–1.5 cm (0.3–0.6 in) broad.^[5]

The flowers are bright red or white, and 3 cm (1+1⁄4 in) or more in diameter, with three to seven petals.^[5][6] Some fruitless cultivars are grown for the flowers alone.^[15] The flower's anthers close around the stigma until maturity, and the ovaries are divided internally into compartments or locules of many suspended ovules covered by a septum.^[16]

The pomegranate fruit husk is red-purple with an outer, hard pericarp, and an inner, spongy mesocarp (white "albedo"), which comprises the fruit's inner wall where seeds attach.^[17] Membranes of the mesocarp are organised as nonsymmetric chambers that contain seeds which are embedded without attachment to the mesocarp,^[17] also a result of fertilisation of the divided ovary. Pomegranate seeds are characterised by having sarcotesta, thick fleshy seed coats derived from the integuments or outer layers of the ovule's epidermal cells.^[18][19] The number of seeds in a pomegranate can vary from 200 to about 1,400.^[20] Botanically, the fruit is a berry with edible seeds and pulp produced from the ovary of a single flower.^[18] The fruit is variable in size, from 2–8 cm (1–3 in) in diameter in wild plants (to 12 cm (4.7 in) in some cultivars) with a rounded shape and thick, reddish husk.^[5][6] In mature fruit, the juice obtained by compressing the seeds yields a tart flavour due to low pH (4.4) and high contents of polyphenols,^[21] which may cause a red indelible stain on fabrics.^[22] The pigmentation of pomegranate juice primarily results from the presence of anthocyanins and ellagitannins.^[21][23]