ː

ː (NOT :)

The symbol ː is used in the International Phonetic Alphabet as a marker of a long vowel. In its most accurate (and pedantic) use, it is to be distinguished from a colon (:): the IPA mark is a triangular colon, formed of two small triangles rather than two dots. In most handwriting, and the work of all but specialized printers, the two are interchangeable.