Source: Noto Sans Math

U+221A Square Root

U+221A was added in Unicode version 1.1 in 1993. It belongs to the block U+2200 to U+22FF Mathematical Operators in the U+0000 to U+FFFF Basic Multilingual Plane.

This character is a Math Symbol and is commonly used, that is, in no specific script. The character is also known as radical sign.

The glyph is not a composition. Its width in East Asian texts is determined by its context. It can be displayed wide or narrow. In bidirectional text it acts as Other Neutral. When changing direction it is mirrored. If its East Asian Width is “narrow”, U+221A forms a word with similar characters, which prevents a line break inside it. Otherwise it allows line breaks around it, except in some numeric contexts.

The CLDR project calls this character “square root” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: radical, radix, root, square, surd.

The Wikipedia has the following information about this codepoint:

In mathematics, the radical symbol, radical sign, root symbol, radix, or surd is a symbol for the square root or higher-order root of a number. The square root of a number x is written as

$\sqrt{x},$
while the nth root of x is written as

$\sqrt[n]{x} .$
It is also used for other meanings in more advanced mathematics, such as the radical of an ideal.
In linguistics, the symbol is used to denote a root word.

Representations

System	Representation
Nº	8730
UTF-8	E2 88 9A
UTF-16	22 1A
UTF-32	00 00 22 1A
URL-Quoted	%E2%88%9A
HTML hex reference	√
Wrong windows-1252 Mojibake	âˆš
HTML named entity	&Sqrt;
HTML named entity	√
alias	radical sign
Encoding: EUC-KR (hex bytes)	A1 EE
Encoding: IBM866 (hex bytes)	FB
Encoding: JIS0208 (hex bytes)	A2 E5
Encoding: JIS0208 (hex bytes)	AD F5
Encoding: KOI8-R (hex bytes)	96
Encoding: KOI8-U (hex bytes)	96
Encoding: MACINTOSH (hex bytes)	C3
Encoding: X-MAC-CYRILLIC (hex bytes)	C3
L^AT_EX	\surd
AGL: Latin-2	radical
AGL: Latin-3	radical
AGL: Latin-4	radical
AGL: Latin-5	radical
Adobe Glyph List	radical
digraph	RT

Elsewhere

Complete Record

Property	Value
Age (age)	1.1 (1993)
Unicode Name (na)	SQUARE ROOT
Unicode 1 Name (na1)	—
Block (blk)	Mathematical Operators
General Category (gc)	Math Symbol
Script (sc)	Common
Bidirectional Category (bc)	Other Neutral
Combining Class (ccc)	Not Reordered
Decomposition Type (dt)	none
Decomposition Mapping (dm)	Square Root
Lowercase (Lower)	✘
Simple Lowercase Mapping (slc)	Square Root
Lowercase Mapping (lc)	Square Root
Uppercase (Upper)	✘
Simple Uppercase Mapping (suc)	Square Root
Uppercase Mapping (uc)	Square Root
Simple Titlecase Mapping (stc)	Square Root
Titlecase Mapping (tc)	Square Root
Case Folding (cf)	Square Root
ASCII Hex Digit (AHex)	✘
Alphabetic (Alpha)	✘
Bidi Control (Bidi_C)	✘
Bidi Mirrored (Bidi_M)	✔
Composition Exclusion (CE)	✘
Case Ignorable (CI)	✘
Changes When Casefolded (CWCF)	✘
Changes When Casemapped (CWCM)	✘
Changes When NFKC Casefolded (CWKCF)	✘
Changes When Lowercased (CWL)	✘
Changes When Titlecased (CWT)	✘
Changes When Uppercased (CWU)	✘
Cased (Cased)	✘
Full Composition Exclusion (Comp_Ex)	✘
Default Ignorable Code Point (DI)	✘
Dash (Dash)	✘
Deprecated (Dep)	✘
Diacritic (Dia)	✘
Emoji Modifier Base (EBase)	✘
Emoji Component (EComp)	✘
Emoji Modifier (EMod)	✘
Emoji Presentation (EPres)	✘
Emoji (Emoji)	✘
Extender (Ext)	✘
Extended Pictographic (ExtPict)	✘
FC NFKC Closure (FC_NFKC)	Square Root
Grapheme Cluster Break (GCB)	Any
Grapheme Base (Gr_Base)	✔
Grapheme Extend (Gr_Ext)	✘
Grapheme Link (Gr_Link)	✘
Hex Digit (Hex)	✘
Hyphen (Hyphen)	✘
ID Continue (IDC)	✘
ID Start (IDS)	✘
IDS Binary Operator (IDSB)	✘
IDS Trinary Operator and (IDST)	✘
IDSU (IDSU)	0
ID_Compat_Math_Continue (ID_Compat_Math_Continue)	0
ID_Compat_Math_Start (ID_Compat_Math_Start)	0
Ideographic (Ideo)	✘
InCB (InCB)	None
Indic Mantra Category (InMC)	—
Indic Positional Category (InPC)	NA
Indic Syllabic Category (InSC)	Other
Jamo Short Name (JSN)	—
Join Control (Join_C)	✘
Logical Order Exception (LOE)	✘
Math (Math)	✔
Noncharacter Code Point (NChar)	✘
NFC Quick Check (NFC_QC)	Yes
NFD Quick Check (NFD_QC)	Yes
NFKC Casefold (NFKC_CF)	Square Root
NFKC Quick Check (NFKC_QC)	Yes
NFKC_SCF (NFKC_SCF)	Square Root
NFKD Quick Check (NFKD_QC)	Yes
Other Alphabetic (OAlpha)	✘
Other Default Ignorable Code Point (ODI)	✘
Other Grapheme Extend (OGr_Ext)	✘
Other ID Continue (OIDC)	✘
Other ID Start (OIDS)	✘
Other Lowercase (OLower)	✘
Other Math (OMath)	✘
Other Uppercase (OUpper)	✘
Prepended Concatenation Mark (PCM)	✘
Pattern Syntax (Pat_Syn)	✔
Pattern White Space (Pat_WS)	✘
Quotation Mark (QMark)	✘
Regional Indicator (RI)	✘
Radical (Radical)	✘
Sentence Break (SB)	Other
Soft Dotted (SD)	✘
Sentence Terminal (STerm)	✘
Terminal Punctuation (Term)	✘
Unified Ideograph (UIdeo)	✘
Variation Selector (VS)	✘
Word Break (WB)	Other
White Space (WSpace)	✘
XID Continue (XIDC)	✘
XID Start (XIDS)	✘
Expands On NFC (XO_NFC)	✘
Expands On NFD (XO_NFD)	✘
Expands On NFKC (XO_NFKC)	✘
Expands On NFKD (XO_NFKD)	✘
Bidi Paired Bracket (bpb)	Square Root
Bidi Paired Bracket Type (bpt)	None
East Asian Width (ea)	ambiguous
Hangul Syllable Type (hst)	Not Applicable
ISO 10646 Comment (isc)	—
Joining Group (jg)	No_Joining_Group
Joining Type (jt)	Non Joining
Line Break (lb)	Ambiguous (Alphabetic or Ideographic)
Numeric Type (nt)	none
Numeric Value (nv)	not a number
Simple Case Folding (scf)	Square Root
Script Extension (scx)
Vertical Orientation (vo)	R