Notar
/ˈnəʊtɑː/(also NOTAR) Aeronautics
noun
Frequently attributive A trademark for a system of helicopter propulsion in which an anti-torque force is generated by the circulation of air through and around the tail boom, thus dispensing with the need for a tail rotor; a helicopter propelled by this system.
Origin
1980s; earliest use found in Business Week. Acronym from the initial letters of no tail rotor.