D defs.my
Entry 1 sense Webster, 1913

Macron

/măkʹrŏn/ · Ma·cron · IPA /ˈmeɪkɹɑn/
01 n. A short, straight, horizontal mark [-], placed over vowels to denote that they are to be pronounced with a long sound; as, ā, in dāme; ē, i…
  1. 1.
    A short, straight, horizontal mark [-], placed over vowels to denote that they are to be pronounced with a long sound; as, ā, in dāme; ē, in sēam, etc.(Pron.)
Syn. macrotone.