Sonar Was Modelled on the Word Radar
Sonar detects objects underwater using sound. Its name copies the pattern of radar, coined a few years earlier.
Sonar detects and locates objects underwater by emitting sound and timing the echo. The word was built to match: *radar* was coined in 1940 from radio detection and ranging, and *sonar* followed in 1942 from sound navigation and ranging, deliberately echoing the pattern. The technology existed first; the name was reverse-engineered to fit. Active sonar sends a pulse and listens for the return; passive sonar only listens, which is why submarines prefer it.
- Underwater sound detection. *Ship's sonar.*
- Active sonar — sends a pulse. *Active sonar.*
- Passive sonar — only listens. *Passive sonar.*
- Radar — the model for the name. *Radar.*
- Coined 1942. *From sound navigation and ranging.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | sonar | Sonar. |
| Type | active sonar | Active sonar. |
| Type | passive sonar | Passive sonar. |
| Related | radar | Radar. |
| Related | echolocation | Echolocation. |
- Sonar picked up a contact.Detection.
- Passive sonar gives away nothing.Tactics.
- The name copies radar.Etymology.
Active and passive sonar
- Active — emits a pulse and times the echo
- It reveals your own position to anyone listening
- Passive — listens only, detecting engine and propeller noise
- Submarines favour passive for exactly that reason
- Bats and dolphins use biological echolocation on the same principle
An acronym of *sound navigation and ranging*, coined in 1942 on the model of *radar*.
What does sonar stand for?
Sound navigation and ranging, coined in 1942 to match the earlier radar.
Why do submarines avoid active sonar?
Because emitting a pulse announces your position to anyone listening. Passive sonar reveals nothing.