Apex (diacritic)

In written Latin, the apex (plural "apices") is a mark with roughly the shape of an acute accent (´) or apostrophe (ʼ) that was sometimes placed over vowels to indicate that they were long.

[3] The grammarian Quintilian wrote that apices are necessary when a difference of quantity in a vowel changes the meaning of a word, as in malus and málus, but recommended against including them otherwise.

[5] Long vowels were never consistently indicated, even within individual inscriptions; writers most often marked them in grammatical endings, to avoid visual confusion with other letters, and to denote phrasal units.

[1] In modern Latin orthography, apices are typically not used, but the acute accent, which is similar in appearance, is sometimes used to mark stressed syllables.

[citation needed] The apex (used above vowels) is often contrasted with the sicilicus, a rarely-attested ancient Latin diacritic used above consonants to denote that they should be pronounced double.