O
O in Morse code
--- · dah dah dah
How to say it
Operators don’t say “dot dash” — they say dah dah dah. Saying the rhythm out loud is the quickest way to make it stick.
Mnemonic
Think: OH MY GOD. Stressed syllables are dahs, unstressed are dits. Use it to get started, then drop it — at real speed you won’t have time to think.
Three dahs. Together with S it forms SOS.
Timing
0 dits and 3 dahs. A dah is three times the length of a dit, with a one-dit gap between each symbol. The whole letter is 11 units long.
Where you learn it
In the Koch order DotDash uses, O is character number 10 of 40. You learn it by sound at full speed, with a new character unlocked each time you reach 90% accuracy.
Easily confused with
Similar rhythms worth comparing side by side: M --.
Words with O
Learn O and the other 39 by ear
DotDash teaches you Morse code in five minutes a day. Start free on iOS and Android.