Negative Acknowledge
NAK
Non-printing control character
Unicode
U+0015
Decimal
21
HTML (numeric)
 · 
Alt code (Windows)
Alt + 21 · Alt + 021
Category
ASCII control
Related characters
FAQ — Negative Acknowledge
What is the Unicode code of ␕ (Negative Acknowledge)?
The Negative Acknowledge character has the Unicode codepoint U+0015 (decimal 21). Its HTML form is  (decimal) /  (hex).
How do I type ␕ with an alt code?
This is a control character and is not usually typed directly. Its code is Alt + 21 · Alt + 021.
Which category does ␕ belong to?
Negative Acknowledge is in the "ASCII control" category.