ma·cron| \ ˈmā-ˌkrän , ˈma-, -krən \
Definition of macron
: a mark − placed over a vowel to indicate that the vowel is long or placed over a syllable or used alone to indicate a stressed or long syllable in a metrical foot
First Known Use of macron
1851, in the meaning defined above
And he causeth all, both small and great, rich and poor, free and bond, to receive a mark in their right hand, or in their foreheads:  And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name.