What does dah mean?
A dah is one of the two fundamental elements of Morse code, alongside the shorter dit (or dot). Sounded aloud, a dah is a sustained tone approximately three times the length of a dit, and in printed representations of code it corresponds to a dash. Every character in the International Morse alphabet — from the simple single-dah for the letter T to more complex combinations — is built entirely from sequences of dits and dahs separated by carefully timed pauses. The word belongs chiefly to the world of amateur radio, telegraphy, and military signalling history, where operators learn to recognize letters by ear rather than by reading dots and dashes on paper. Though niche, it remains current among radio hobbyists and anyone studying communication history.
nounA dah is the longer of the two signal elements used in Morse code, roughly three times the duration of a dot (dit), and sounded or transmitted as a sustained tone or mark.
- The long signal element in Morse code, roughly three times the length of a dit, corresponding to what is written in print as a dash.
"The operator tapped out a crisp dit followed by a long dah."
"The letter T is simply a single dah."
"Learning Morse by ear means training yourself to hear each dah as three dits long."
Standard regular plural, used mainly in discussions of Morse code timing and transmission.
"The message contained more dahs than dits."
In Morse code, every letter you've ever spelled is built from just two sounds — the snappy dit and its big brother, the dah.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of dah
The word dah arose in the nineteenth century as an onomatopoeic rendering of the sound of the longer Morse code element when keyed on a telegraph sounder or sounded as a tone. It was coined by telegraphers themselves to give a pronounceable name to what written notation called a dash, pairing naturally with "dit" for the shorter dot. Both terms entered English through the practical speech of railway and commercial telegraph operators and survive today mainly in amateur radio circles.
How dah is actually used
"Dah" is the spoken form used when Morse code is sounded aloud; "dash" is the equivalent term in written or technical contexts.
Easily confused with dah
A dit (or dot) is the short element of Morse code, whereas a dah is the long element lasting about three times as long.