Dah

Dah is the term used in Morse code to denote a long signal, commonly called a dash in general spelling. It contrasts with 'dit' or 'dot', the short signal. Together, dits and dahs form the basic building blocks of Morse code, which encodes letters and numerals as sequences of audible or visual pulses. The word 'dah' reflects the perceptual length of the signal and is widely used in instructional materials and operator manuals.

In practice, each character is represented by a specific pattern of dits and dahs. For example, the letter A is dit-dah, B is dah-dit-dit-dit, and M is dah-dah. The timing framework defines one unit as the duration of a dit; a dah lasts three units. The gap between elements is one unit, between letters three units, and between words seven units. Mastery requires maintaining consistent rhythm to distinguish the elements and to prevent ambiguity in reception. The dah is also used in prosigns and when spelling out longer phrases in Morse code.

Beyond describing signals in Morse code, the term 'dah' has limited use in other domains. It is most frequently encountered in amateur radio literature, training guides, and historical descriptions of telegraphy, where it helps differentiate the long element from the short 'dit' in written notation.