:Centralised:

Pronunciation ˈsentrəlaɪzd

A centralised vowel is one which is located other than at the periphery of the vowel quadrilateral, but is not within the central triangle of the quadrilateral. Centralisation is symbolised by the use of a diaeresis diacritic (U+0308) placed over a vowel symbol, as in [ɛ̈]. Notice that centralised and central are distinct terms.