mainstaysomeone or something which something is based on or depends onAlthough tourism is the economic mainstay, there is some other industry, including printing and electronics and the production of paper, cheese, textiles, and animal foodstuffs. The Irishman who came to Hillsborough as a' development player' has been a mainstay in Paul Sturrock's squad in recent weeks despite not hitting the target. One of the mainstays was lutfisk, which was always served with boiled potatoes and a white sauce. ofBurn FM was first launched in 1995, and since then has become a mainstay of student life. Surgery is the mainstay of treatment for varicose veins in many patients. The lecture discusses the conflict between fishermen and marine mammals and how it is managed in an area where fishing is still the mainstay of the economy and marine mammals are by many seen as competitors for scarce resources, even as pest. Sedums and hardy fuchsias are mainstays of my October garden. Doxorubicin, a mainstay drug of chemotherapy, can cause heart damage, while another anti-cancer agent, cis-platinum, can harm the kidneys. Glenn Stephenson, J.C. Nichols ' director of asset management and leasing, said the company needed a mix of mainstay shops like the Gap and one-of-a-kind stores like Pinstripes. The multinationals have also helped the growth of mainstay industries in the metropolis. a stay which stretches from the maintop to the bottom of the foremast of a sailing boat