Oscar (Phonetic Alphabet)

The international radiotelephony spelling word for the letter O.

It is used to spell call signs, identifiers and words clearly over voice radio. The prescribed spoken form is represented as ‘OSS CAH’, with emphasis indicated in official pronunciation tables.

In the International Code of Signals, the single flag O means ‘Man overboard’, a separate use from spelling the letter. Context is therefore important, and an actual person-overboard emergency should be communicated through the vessel’s established alarm and radio procedures rather than by assuming the word alone is understood as a distress report.