A macron, from the Greek (makrón), meaning "long", is a diacritic placed above a vowel (and, more rarely, under a consonant). It was originally used to mark a long syllable in Græco-Roman metrics, but now also indicates that the vowel is long. (The opposite is a breve ˘, used to indicate originally a short syllable and now also a short vowel.) Distinct… (More on Macron)