Search Result for "macron": 
Wordnet 3.0

NOUN (1)

1. a diacritical mark (-) placed above a vowel to indicate a long sound;


The Collaborative International Dictionary of English v.0.48:

Macron \Ma"cron\, n. [NL., fr. Gr. ? long.] (Pron.) A short, straight, horizontal mark [-], placed over vowels to denote that they are to be pronounced with a long sound; as, [=a], in d[=a]me; [=e], in s[=e]am, etc. Syn: macrotone. [1913 Webster]
WordNet (r) 3.0 (2006):

macron n 1: a diacritical mark (-) placed above a vowel to indicate a long sound