rambutan, (Nephelium lappaceum), tree of the soapberry family (Sapindaceae). It is native to Malaysia, where it is commonly cultivated for its tasty fruit, also called rambutan. The bright-red, oval fruit, about the size of a small hen’s egg, is covered with long, soft spines and has a tasty acid pulp. The tree grows to about 10.5–12 metres (35–40 feet).