The okina () is the letter that transcribes the glottal stop consonant in Hawaiian. It does not have distinct uppercase and lowercase forms, and is represented electronically by the modifier letter turned comma: .
A phonemic glottal stop exists in many other Polynesian languages as well; these are usually written by a similar apostrophe-like letter.
Following are the names of the glottal stop consonant in various Polynesian languages, and notes on how they are represented in text.
In many typefaces, the symbol for the ûokina looks identical to the symbol for the curved single opening quotation mark. In others (like Linux Libertine) it is a slightly different size, either larger or smaller, as seen in the adjacent image.
The phrase illustrated is surrounded by single opening and closing quotation marks. There is one ûokina before the à  and another one before the last i. These are slightly smaller than the quotation marks in the first line and slightly larger in the second.
The okina is treated as a separate letter in the Hawaiian alphabet. It is used only before vowels: a, e, i, o, u. It is unicameralâÂÂthat is, it does not have separate uppercase (capital or majuscule) and lowercase (small or minuscule) formsâÂÂunlike the other letters, all of which are basic Latin letters. For words that begin with an okina, capitalization rules affect the vowel: for instance, at the beginning of a sentence, the name of the letter is written "Okina", with a capital O.
The United States Board on Geographic Names lists relevant place names both with and without the okina and kahakà  (macron) in the Geographic Names Information System. Colloquially and formally, the forms have long been used interchangeably.
In the (limited) ASCII character set, the okina was typically represented by the apostrophe character (), conventionally a straight typewriter apostrophe, thus lacking the curve of the okina proper. In some computer fonts, the ASCII apostrophe is rendered as a right single quotation mark, which is an even less satisfactory glyph for the okinaâÂÂessentially a 180ð rotation of the correct shape.
Many subsequent "extended ASCII" character sets expanded on the overloaded ASCII apostrophe, providing distinct characters for the left and right single quotation marks. The left single quotation mark has been used as an acceptable approximation to the okina, though it still has problems: the okina is a letter, not a punctuation mark, which may cause incorrect behaviour in automated text processing. Additionally, the left single quotation mark is represented in some typefaces by a glyph shaped like a mirrored miniature (rather than like a ), and thus unsuitable for the okina.
In the Unicode standard, the okina is encoded as (). It can be rendered in HTML by the entity <code>&#699;</code> (or in hexadecimal form <code>&#x02BB;</code>).
Although this letter was introduced in Unicode 1.1 (1993), lack of technical support for this character prevented its easy and universal use for many years. Since about 2008, OS X, Microsoft Windows and Linux-based computers and all new major smartphones have had no problem with correctly rendering the glyph. Consequently, U+02BB should be the value used in encoding new data when the expected use of the data permits.