Military Alphabet · Letter O
O in the Military Alphabet: Oscar
Code word, pronunciation, history, and how to use it when spelling out loud
In the military alphabet, the letter O is Oscar, pronounced OSS-cah. Oscar has stood for O since ICAO's 1951 alphabet and passed the 1956 review unchanged. Saying 'O as in Oscar' also keeps the letter O from being taken for the digit zero.
Why "Oscar"?
Oscar is a given name in use across much of Europe, from Scandinavia to Spain, which suited the selection brief: ICAO wanted words that speakers of many languages would recognize and pronounce consistently. The candidate lists were assembled in the late 1940s with Jean-Paul Vinay, a linguistics professor at the Université de Montréal. Unlike its neighbors Mike and November, Oscar was not among the words flagged for replacement after the 1951 alphabet entered service — it appeared in 1951 and simply stayed.
O Across Spelling Alphabets
| Alphabet | Word for O |
|---|---|
| NATO/ICAO | Oscar |
| LAPD | Ocean |
| Western Union | Ocean |
| German (Classic) | Otto |
| German (DIN 5009:2022) | Offenbach |
| French | Oscar |
| Spanish | Oviedo |
| Italian | Otranto |
| Able Baker (WWII, historical) | Oboe |
| RAF 1924 (historical) | Orange |
For two decades the RAF spelled O as Orange, a holdover from its 1924 alphabet. The wartime Able Baker alphabet switched to Oboe — a word that, coincidentally, was also the codename of a British blind-bombing navigation system. Oscar took over in 1951.
Oscar in the Field
At sea the Oscar flag — divided diagonally, red over yellow — means 'man overboard,' and it lends its name to the man-shaped dummy navies throw into the water for rescue drills. Cold War watchers know the Oscar class: the giant Soviet cruise-missile submarines of Projects 949 and 949A, one of which, Kursk, was lost in the Barents Sea in 2000. In everyday spelling traffic, 'O as in Oscar' does steady work separating the letter O from zero.
"O as in Oscar" on the Phone
Bode, with a silent E — B as in Bravo, O as in Oscar, then D and E.
More on spelling out names and codes call-side in the phone spelling guide, and every letter's "as in" word is on the letters-as-words page. To convert whole words instantly, use the free military alphabet translator.
ONE TO REMEMBER
US Navy crews call their man-overboard training dummy Oscar, after the signal flag that is hoisted when someone actually goes into the water.
Frequently Asked Questions
What is O in the military alphabet?
O is Oscar in the NATO phonetic alphabet. It has represented the letter O since ICAO introduced it in 1951, and it doubles as a guard against confusing the letter O with the number zero.
How do you pronounce Oscar?
OSS-cah, with the stress on the first syllable. ICAO's official respelling omits the final R, reflecting non-rhotic pronunciation, though saying the R as in ordinary English is universally understood.
What was O before Oscar?
The RAF's 1924 alphabet used Orange, and the WWII Able Baker alphabet used Oboe. Oscar replaced Oboe in ICAO's 1951 alphabet and survived the 1956 revision without change.
What does the Oscar flag mean at sea?
Man overboard. In the International Code of Signals, the O flag — red and yellow, divided diagonally — is hoisted when a person has gone into the water.
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Make It Automatic
Reading is recognition; games are recall. Drill all 26 letters until Oscar answers itself.