'radar' originates from English, specifically the acronym 'RAdio Detection And Ranging', where 'radio' meant 'wireless transmission' and 'detection' meant 'discovering the presence of something'.

'RAdio Detection And Ranging' was shortened to 'radar' during World War II and eventually became the modern English word 'radar'.

Initially, it meant 'a system for detecting objects using radio waves', and this meaning has largely remained the same in modern usage.