Medium-sized tree up to 30 m tall; bole often short and much-branched, up to 100 cm in diameter, often with short and blunt buttresses; outer bark of older trees scaly and reddish brown; crown rounded.
Leaves alternate, paripinnate with 2–4(–5) pairs of leaflets; stipules absent; leaflets opposite, ovate-lanceolate to ovate-elliptical, (4–)5–6(–8) cm × (1.5–)2.5–3.5 cm, entire, glabrous, pinnately veined. Inflorescence an axillary panicle (5–)8–15(–18) cm long, consisting of small cymes.
Flowers unisexual, but with well-developed vestiges of the opposite sex, regular, 5-merous, small; pedicel slender, 1.5–3 mm long; calyx with broadly rounded lobes 1–1.5 mm long, glabrous; petals free, slightly contorted in bud, ovate-oblong, 3–4.5 mm long, glabrous; stamens united into a tube, with 10 sessile anthers at the mouth of the tube; disk annular; ovary superior, usually 5-celled, style short, with disk-shaped stigma.
Fruit a woody, ovoid to almost globose capsule (4.5–)6–10 cm long, dark brown or blackish, opening by 5 valves, many-seeded.
Seeds winged, flat, (2–)4–5(–6) cm long, dark brown, hanging down and overlapping in fruit.
Seedling with hypogeal germination; cotyledons thin; first leaves simple, later ones 3-foliolate or imparipinnate before becoming paripinnate.
 
 
Uses
Swietenia wood (mahogany) is regarded as the world’s finest timber for high-class furniture and cabinet work. Its popularity is especially due to its attractive appearance in combination with ease of working, excellent finishing qualities and dimensional stability. It is also often used for interior trim such as panelling, doors and decorative borders. It is used for boat building, often as a decorative wood for luxury yachts and ocean liners, but sometimes also as plywood for planking and deck housing. Its outstanding technical qualities make it particularly suitable for precision woodwork such as models and patterns, instrument cases, clocks, printer’s blocks and parts of musical instruments; for these purposes, uniform straight-grained material is used. Other minor uses include burial caskets, wood carvings, novelties, toys and turnery.
An oil can be extracted from the seed kernels which might be of some commercial value. The bark has been used for dyeing and tanning leather. Various medicinal uses of various parts of the tree are reported from tropical America. The crushed fruit shells have been used as a potting medium. Swietenia mahagoni is also used in reforestation programmes and as a shade tree in young plantations of other timber species, and is occasionally planted as an ornamental.