English radar (pronounced [ˈreɪdɑɹ] ), from radio detection and ranging.
The English acronyms NATO, FOP and FEC are made out of North Atlantic Treaty Organization, First Order Principle and Free Element Condition, respectively. Some Dutch examples are: TROS, KNAV and DAF.
Acronyms contrast with alphabetisms, which are pronounced with the names of the letters (e.g. CD, HTML).
Sometimes acronym is used for abbreviations more generally, i.e. also for alphabetisms.
From Greek akro- 'tip' and -oonym- 'name'. The first attestation in the OED is from 1943.