Why U matters
U is the exact reverse of D in morse: D is dash-dot-dot, U is dot-dot-dash. Learning reversals in pairs (A/N, D/U, G/W) is one of the fastest routes through the alphabet.
Memorization tip
“di-di-DAH” — two short, one long. Reverse of D.
Common English words starting with U
Where this letter appears in the ITU alphabet
The full A–Z chart shows every letter side-by-side so you can see the pattern of dots and dashes. For just the numbers, see morse code numbers 0–9. For a printable version, the chart page combines letters, digits, and punctuation in one layout.
The history of U
U is one of the youngest English letters. For most of its history U and V were the same letter, used interchangeably depending on position in the word (V at the start, U in the middle). The split into separate vowel and consonant forms was made systematic by Pierre Ramus in the 1500s and slowly adopted in English over the following two centuries. This is why old English manuscripts and Roman inscriptions can look strange: 'IVLIVS CAESAR' is the same as 'JULIUS CAESAR'.
U in CW operating
U has no standalone prosign role but appears in UR ('your', a contraction used constantly in signal reports — 'UR RST 599' means 'your signal is 5-9-9'). U also features in the all-important morse abbreviation U (just the letter), informally used to mean 'you' in casual on-air chat. The 73-style sign-offs almost always include 'TU' meaning 'thank you'.
What position 13 means in practice
U at position 13 with 2.8% frequency means about one U every thirty-five characters of running English — modest but boosted in CW by the constant use of UR ('your') in signal reports. As the only vowel in the high-frequency word 'us' and a key vowel in 'use', 'up', 'under', 'until', U appears more often than its raw rank suggests. The exact-reverse-of-D structure makes it one of the canonical Koch reversal pairs alongside A/N and G/W. Drilling reversal pairs as single units rather than as separate letters is the fastest path through the four-element family of codes.
How to drill it
U is the exact reverse of D — drill them as a pair from the first session you cover them. The classic confusion is V (di-di-di-dah, three dots and a dash) — U has only two dots. Wait for the dash to arrive after exactly two dots. Pair U with V in tight rotation and the third-dot-versus-no-third-dot distinction locks within a session.
Most-confused with: V, D, F — drill them together.
Sample copy: “Use up unused cups under the umbrella.”
Frequently asked questions
What is the letter U in morse code?
The letter U in international morse code is "..-" — 3 symbols.
How do I remember the morse code for U?
"di-di-DAH" — two short, one long. Reverse of D.
How common is the letter U in English?
U is position 13 in English frequency, appearing in about 2.8% of running text.