[2] The generic name Varanus is derived from the Arabic word ورل waral [Standard Arabic] / ورر warar [colloquially] / ورن waran [colloquially], from a common Semitic root ouran, waran, warar or waral, meaning "lizard beast".

[6] Austronesian languages spoken across Southeast Asia, where varanids are common, have a large number of slightly related local names for them.

They are usually known as biawak (Malay, including Indonesian standard variety), bayawak (Filipino), binjawak or minjawak or nyambik (Javanese), or variations thereof.

[8][9] In South Asia, they are known as hangkok in Meitei, mwpou in Boro, ghorpad घोरपड in Marathi, uḍumbu உடும்பு in Tamil and udumbu ഉടുമ്പ് in Malayalam, bilgoh in Bhojpuri, gohi (गोहि) in Maithili, in Sinhala as තලගොයා / කබරගොයා (talagoya [land monitor] / kabaragoya [water monitor where kabara means vitiligo]), in Telugu as uḍumu (ఉడుము), in Kannada as uḍa (ಉಡ), in Punjabi and Magahi as गोह (goh), in Assamese as gui xaap, in Odia as ଗୋଧି (godhi), and in Bengali as গোসাপ (goshaap) or গুইসাপ (guishaap), and गोह (goh) in Hindi and गोधा (godhā) in Sanskrit.

The various species cover a vast area, occurring through Africa, the Indian subcontinent, to China, the Ryukyu Islands in southern Japan, south to Southeast Asia to Thailand, Malaysia, Brunei, Indonesia, the Philippines, New Guinea, Australia, and islands of the Indian Ocean and the South China Sea.

They have also been introduced outside of their natural range, for instance, the West African Nile monitor is now found in South Florida.

[12] Monitor lizards also occurred widely in Europe in the Neogene, with the last known remains in the region dating to the Middle Pleistocene.

[13] Most monitor lizards are almost entirely carnivorous,[14] consuming prey as varied as insects, crustaceans, arachnids, myriapods, molluscs, fish, amphibians, reptiles, birds, and mammals.

[16][17][18] Monitor lizards are considered unique among animals in that its members are relatively morphologically conservative, yet show a very large size range.

[20][21] Monitor lizards maintain large territories and employ active-pursuit hunting techniques that are reminiscent of similar-sized mammals.

Monitor lizards are oviparous,[23] laying from seven to 38 eggs,[27] which they often cover with soil or protect in a hollow tree stump.

[36] Blue and green tree monitors in British zoos have been observed shredding leaves, apparently as a form of play.

[3] Monitor lizards are poached in some South- and Southeast Asian countries, as their organs and fat are used in some traditional medicines, although there is no scientific evidence as to their effectiveness.

[38][39] Monitor lizard meat, particularly the tongue and liver, is eaten in parts of India and Malaysia and is supposed to be an aphrodisiac.

Monitor lizard skins are prized in making the resonant part of serjas (Bodo folk sarangis) and dotaras (native strummed string instruments of Assam, Bengal and other eastern states).

[47] In Kerala, Andhra Pradesh, Karnataka, Telangana and all other parts of South India, catching or killing of monitor lizards is banned under the Protected Species Act.