'u' originates from Latin script, ultimately traced back to the Phoenician letter 'waw'. In Medieval and Classical Latin the shape was written as 'V', and the distinct rounded form 'U' later developed to represent the vowel sound.

'u' changed from the Latin letter written as 'V' (used for both vowel and consonant) through medieval scribal forms that distinguished a rounded vowel form 'u' from the pointed consonant form 'v', eventually becoming the modern letter 'u'. The original sign traces back through Etruscan and Greek forms to Phoenician 'waw'.

Initially the character represented a consonant (and later both consonant and vowel values); over time it evolved into the specific vowel letter 'u' in modern usage, with the consonant value represented separately as 'v'.