Kahakō

A macron, from Greek  (makrón) meaning "long", is a diacritic ¯ placed over a vowel which was originally used to mark a long (i.e. heavy) syllable in Græco-Roman metrics, but has now been taken also to indicate that the vowel is long. The opposite is a breve ˘, used to indicate originally a short syllable and now also a short vowel. Distinctions between long and short vowels are usually phonemic. The sign to indicate a long vowel in the International Phonetic Alphabet is a modified triangular colon.
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