Behind every accented O on your screen is a Unicode code point, a number that identifies the character across every device and font in the world. Understanding how Unicode handles accents explains why some accented O characters behave differently in search, sorting and text processing. This guide makes the concepts clear.
What A Code Point Is
Unicode assigns each character a unique number called a code point, written in the form U plus four or more hexadecimal digits. The acute O is U+00D3, the two dot O is U+00D6, and the macron O is U+014C. That number is the character's true identity; the shape you see is just one font's drawing of it.
Because the code point is universal, copying U+00D3 from one program and pasting it into another moves the exact same character, regardless of platform. This is what makes copy and paste reliable across systems.
Precomposed Versus Combining
Here is the subtlety that trips people up. There are two ways to represent an accented O in Unicode. The first is a single precomposed code point, like U+00D3, which is the whole accented character in one unit. The second is a base O followed by a separate combining accent code point, which the software stacks together to draw the same shape.
Two accented O characters can look identical yet be stored differently: one as a single precomposed code point, the other as an O plus a combining mark. To a human they match; to a computer they may not.
Why The Difference Matters
When text uses combining marks, a search for the precomposed character may fail to match, because the byte sequences differ even though the display is the same. Sorting can behave unexpectedly for the same reason. This is why systems often normalise text, converting everything to one consistent form before comparing.
Normalisation
Unicode defines normalisation forms that convert text to a canonical representation. One form composes characters into precomposed code points where possible; another decomposes them into base plus combining marks. Applications that handle names, search or deduplication usually normalise text so that visually identical strings compare as equal.
For everyday copying you rarely need to think about this, because the finder outputs precomposed characters, which are the most widely compatible. It matters mainly for developers processing text at scale.
Where The O Accents Live
The common accented O characters sit in the Latin-1 Supplement and Latin Extended-A blocks of Unicode, with the Vietnamese forms in Latin Extended Additional. The tool shows each character's code point so you can see exactly which one you are copying.
Sorting And Collation
How accented O sorts relative to plain O depends on the language. Some languages treat the accented form as a variant of O for sorting; others, like Danish with its stroke O, place it in its own position near the end of the alphabet. This language dependent ordering is called collation, and it is why the same list can sort differently in different locales.
In Summary
Every accented O is a Unicode code point, such as U+00D3 for Ó, and it can be stored either precomposed or as a base letter plus a combining mark. That distinction affects search and sorting, which is why software normalises text. For copying, the precomposed characters the finder provides are the safe, widely compatible choice.