The trees range from 40 to 60 feet (12–18 m)(if it grows to maturity) high with short trunk and round-topped head. The juice is milky and acrid. The roots are thick, fleshy, covered with bright orange bark.

The leaves are arranged alternately in a slender growing shoot 3–4 feet (91–122 cm) long, varying from dark to pale tender green. In form they are very simple, a long oval terminating in a slender point. In the axil of every growing leaf is found a growing spine which when mature is about 1 inch (2.5 cm) long, and rather formidable. The pistillate and staminate flowers are on different trees; both are inconspicuous; but the fruit is very much in evidence. This in size and general appearance resembles a large, yellow green orange; only its surface is roughened and tuberculated. It is, in fact, a compound fruit such as botanists call a syncarp, in which the carpels (that is, the ovaries) have grown together; thus, the great orange-like ball is not one fruit but many. It is heavily charged with milky juice which oozes out at the slightest wounding of the surface. Although the flowering is dioecious, the pistillate tree even when isolated will bear large oranges, perfect to the sight but lacking the seeds.
Bark: Dark, deeply furrowed, scaly. Branchlets at first bright green, pubescent, during first winter they become light brown tinged with orange, later they become a paler orange brown. Branches with yellow pith, and armed with stout, straight, axillary spines.
Wood: Bright orange yellow, sapwood paler yellow; heavy, hard, strong, flexible, capable of receiving a fine polish, very durable in contact with the ground. It has a specific gravity of 0.7736 or 773,6 kg/m3 (1 ft3of the wood has a weight of 48.21 lb).
Winter buds: All buds lateral. Depressed-globular, partly immersed in the bark, pale chestnut brown.
Leaves: Alternate, simple, 3–5 inches (7.6–12.7 cm) long, 2–3 inches (5.1–7.6 cm) wide, ovate to oblong-lanceolate, entire, acuminate, or acute or cuspidate, rounded, wedge-shaped or subcordate at base. Feather-veined, midrib prominent. They come out of the bud involute, pale bright green, pubescent and tomentose, when full grown are thick, firm, dark green, shining above, paler green below. In autumn they turn a clear bright yellow. Petioles slender, pubescent, slightly grooved. Stipules small, caducous.
Flowers: June, when leaves are full grown; dioecious. Staminate flowers in racemes, borne on long, slender, drooping peduncles developed from the axils of crowded leaves on the spur-like branchlets of the previous year. Racemes are short or long. Flowers pale green, small. Calyx hairy, four-lobed. Stamens four, inserted opposite lobes of calyx, on the margin of thin disk; filaments flattened, exerted; anthers oblong, introrse, two-celled; cells opening longitudinally; ovary wanting. Pistillate flowers borne in a dense globose many-flowered head which appears on a short stout peduncle, axillary on shoots of the year. Calyx, hairy, four-lobed; lobes thick, concave, investing the ovary, and inclosing the fruit. Ovary superior, ovate, compressed, green, crowned by a long slender style covered with white stigmatic hairs. Ovule solitary.
Fruit: Pale green globe, 4–5 inches (10–13 cm) in diameter, made up of numerous small drupes, crowded and grown together. These small drupes are oblong, compressed, rounded, often notched at the apex. They are filled with milky, latex-based juice. The seeds are oblong. The fruit is often seedless, and sinks.[9]

Quercus Robur is a large deciduous tree, with circumference of grand oaks from 4 m (13 ft) to exceptional 12 m (39 ft).[citation needed] The Majesty Oak with a circumference of 12.2 m (40 ft) is the thickest tree in Great Britain,[citation needed] and the Kaive Oak in Latvia with a circumference of 10.2 m (33 ft) is the thickest tree in Northern Europe.[citation needed] Q. robur has lobed and nearly sessile (very short-stalked) leaves 7–14 cm (2.8–5.5 in) long. Flowering takes place in mid spring, and their fruit, called acorns, ripen by the following autumn. The acorns are 2–2.5 cm (0.79–0.98 in) long, pedunculate (having a peduncle or acorn-stalk, 3–7 cm (1.2–2.8 in) long) with one to four acorns on each peduncle. It is a long-lived tree, with a large wide spreading crown of rugged branches. While it may naturally live to an age of a few centuries, many of the oldest trees are pollarded or coppiced, both pruning techniques that extend the tree's potential lifespan, if not its health. Two individuals of notable longevity are the Stelmuž? Oak in Lithuania and the Granit Oak in Bulgaria, which are believed to be more than 1,500 years old, possibly making them the oldest oaks in Europe; another specimen, called the 'Kongeegen' ('Kings Oak'), estimated to be about 1,200 years old, grows in Jaegerspris, Denmark.[citation needed] Yet another can be found in Kvilleken, Sweden, that is over 1,000 years old and 14 metres (46 ft) around.[2] Of maiden (not pollarded) specimens, one of the oldest is the great oak of Ivenack, Germany. Tree-ring research of this tree and other oaks nearby gives an estimated age of 700 to 800 years old. Also the Bowthorpe Oak in Lincolnshire, England is estimated to be 1,000 years old, making it the oldest in the UK, although there is Knightwood Oak in the New Forest which is also said to be as old. Highest density of the grand oak trees Q. robur with a circumference 4 metres (13 ft) and more is in Latvia.[3]