U+0399 "Ι" Greek Capital Letter Iota Unicode Character

U+0399 "Ι" Greek Capital Letter Iota is the uppercase form of the ninth letter of the Greek alphabet, representing the vowel sound /i/ in both Ancient and Modern Greek. It is visually identical to the Latin capital letter I and has a long history in writing, mathematics, and science, where it often symbolizes index variables, the imaginary unit, or identity matrices depending on context. This character is distinct from the Latin letter I in its encoding and usage within Greek text, and it forms a key part of the Greek script used in scholarly works, religious texts, and modern Greek language publications.

General Properties

Code Point	U+0399
Version Added	1.1
Name	Greek Capital Letter Iota
Block	Greek and Coptic
General Category	Uppercase Letter
Canonical Combining Class	Not Reordered
Bidirectional Class	Left To Right

Encodings

HTML Decimal Encoding	Ι
HTML Hex Encoding	Ι
UTF-8 Encoding	0xCE 0x99
UTF-16 Encoding	0x0399
UTF-32 Encoding	0x00000399
C/C++/Java Escape	\u0399

Unicode Properties

NFC Quick Check	Yes
NFD Quick Check	Yes
NFKC Quick Check	Yes
NFKD Quick Check	Yes
Numeric Type	None
Numeric Value	NaN
Line Break	Alphabetic
East Asian Width	Ambiguous
Uppercase	Yes
Simple Lowercase Code Point	"ι" U+03B9 Greek Small Letter Iota
Lowercase Code Point	"ι" U+03B9 Greek Small Letter Iota
Simple Case Folding	"ι" U+03B9 Greek Small Letter Iota
Case Folding	"ι" U+03B9 Greek Small Letter Iota
Cased	Yes
Changes When Casefolded	Yes
Changes When Casemapped	Yes
Changes When Lowercased	Yes
Changes When NFKC Casefolded	Yes
NFKC Casefold	"ι" U+03B9 Greek Small Letter Iota
NFKC Simple Casefold	"ι" U+03B9 Greek Small Letter Iota
Script	Greek
Script Extensions	Greek
Indic Syllabic Category	Other
ID Start	Yes
XID Start	Yes
ID Continue	Yes
XID Continue	Yes
Alphabetic	Yes
Vertical Orientation	Rotated
Grapheme Base	Yes
Grapheme Cluster Break	Other
Word Break	Alphabetic letter
Sentence Break	Upper