The bark is pale brown or grayish, smooth or finely fissured and flaking, armed with long straight spines, 1.2-2.5 cm singly or in pairs, often with slimy sap oozing out from cut parts. The gum is also described as a clear, gummy sap, resembling gum arabic, which exudes from wounded branches and hangs down in long strands, becoming gradually solid. It is sweet at first taste and then irritating to the throat. The leaf is trifoliate, alternate, each leaflet 5-14 x 2–6 cm, ovate with tapering or pointed tip and rounded base, untoothed or with shallow rounded teeth. Young leaves are pale green or pinkish, finely hairy while mature leaves are dark green and completely smooth. Each leaf has 4-12 pairs of side veins which are joined at the margin.
The flowers are 1.5 to 2 cm, pale green or yellowish, sweetly scented, bisexual, in short drooping unbranched clusters at the end of twigs and leaf axils. They usually appear with young leaves. The calyx is flat with small teeth. The four or five petals of 6–8 mm overlap in the bud. Many stamens have short filaments and pale brown, short style anthers. The ovary is bright green with an inconspicuous disc.
The bael fruit typically has a diameter of between 5 and 12 cm. It is globose or slightly pear-shaped with a thick, hard rind and does not split upon ripening. The woody shell is smooth and green, gray until it is fully ripe when it turns yellow. Inside are 8 to 15 or 20 sections filled with aromatic orange pulp, each section with 6 (8) to 10 (15) flattened-oblong seeds each about 1 cm long, bearing woolly hairs and each enclosed in a sac of adhesive, transparent mucilage that solidifies on drying. The exact number of seeds varies in different publications.
The fruits can be eaten either fresh from trees or after being dried and produced into candy, toffee, pulp powder or nectar. If fresh, the juice is strained and sweetened to make a drink similar to lemonade. It can be made into sharbat or Bela pana, a beverage. Bela Pana made in Odisha has fresh cheese, milk, water, fruit pulp, sugar, crushed black pepper, and ice. Bæl pana, a drink made of the pulp with water, sugar, and citron juice, is mixed, left to stand a few hours, strained, and put on ice. One large bael fruit may yield five or six liters of sharbat. If the fruit is to be dried, it is usually sliced and sun-dried. The hard leathery slices are then immersed in water. The leaves and small shoots are eaten as salad greens.