Zero-width non-joiner
The zero-width non-joiner (ZWNJ) is a non-printing character used in the computerization of writing systems that make use of ligatures. When placed between two characters that would otherwise be connected into a ligature, a ZWNJ causes them to be printed in their final and initial forms, respectively. This is also an effect of a space character, but a ZWNJ is used when it is desirable to keep the words closer together.
The ZWNJ is encoded in Unicode as U+200C zero width non-joiner (HTML: ‌ ‌).
Use of the ZWNJ for correct typography
In certain languages, the ZWNJ is required for correct typography.
| Correct (with ZWNJ) | Incorrect | Meaning | ||||
|---|---|---|---|---|---|---|
| Display | Picture | Code | Display | Picture | Code | |
| میخواهم |  |
می‌خواهم(rendered from right to left): می‌خواهم |
میخواهم |  |
میخواهم |
Persian 'I want to' |
| עֲוֹנֹת |  |
עֲו‌ֹנֹת(rendered from right to left): עֲו‌נֹת |
עֲוֹנֹת |  |
עֲוֹנֹת |
Old Hebrew 'transgressions' |
| Auflage |  |
Auf‌lage |
Auflage |  |
Auflage |
German 'edition' (compound of "auf"+"Lage") |
| Brotzeit |  |
Brot‌zeit |
 |
Brotzeit |
German (regional) '(kind of) snack' (compound noun "Brot"+"Zeit" = 'bread time'), shown in Fraktur | |
With the Biblical Hebrew example, the placement of the holam dot to the left of the letter vav ⟨ו⟩ is correct for the translation. The placement of the dot over the ⟨ו⟩ makes it visually confusing with ⟨עוֹנוֹת⟩, "seasons". In Modern Hebrew, there is no reason to use the ḥolam after the vav, and the ligature is not needed, so it is rarely used in Modern Hebrew typesetting.
In German typography, ligatures may not span across the constituent boundaries within compounds. Thus, in the first German example, the prefix Auf- is separated from the rest of the word in order to break the ligature fl into the separate characters f and l.
Use of the ZWNJ for displaying alternate forms
In the Indic scripts, insertion of a ZWNJ after a consonant with a halant or before a dependent vowel will prevent the characters from being joined properly. For example,
In Devanagari, the characters क् and ष typically combine to form क्ष, but when a ZWNJ is inserted between them, क्ष (code: क्‌ष) is seen instead.
In Kannada, the characters ನ್ and ನ combine to from ನ್ನ, but when a ZWNJ is inserted between them, ನ್ನ would be seen. This style is typically used to write non-Kannada words in Kannada script. Ex: Facebook is written as ಫೇಸ್ಬುಕ್, though it can be written as ಫೇಸ್ಬುಕ್.
Symbol
The symbol to be used on keyboards which enable the input of the ZWNJ directly is standardized in Amendment 1 (2012) of ISO/IEC 9995-7:2009 "Information technology – Keyboard layouts for text and office systems – Symbols used to represent functions" as symbol number 81, and in IEC 60417 "Graphical Symbols for use on Equipment" as symbol no. IEC 60417-6177-2.