# Kappa

Variant kappa
Greek word καί written with a handwritten variant of kappa, from the Byzantine period

Kappa (/ˈkæpə/;[1] uppercase Κ, lowercase κ or cursive ϰ; Greek: κάππα, káppa) is the 10th letter of the Greek alphabet, representing the voiceless velar plosive IPA: [k] sound in Ancient and Modern Greek. In the system of Greek numerals, has a value of 20. It was derived from the Phoenician letter kaph . Letters that arose from kappa include the Roman K and Cyrillic К. The uppercase form is identical to the Latin K.

Greek proper names and placenames containing kappa are often written in English with "c" due to the Romans' transliterations into the Latin alphabet: Constantinople, Corinth, Crete. All formal modern romanizations of Greek now use the letter "k", however.[citation needed]

The cursive form ϰ is generally a simple font variant of lower-case kappa, but it is encoded separately in Unicode for occasions where it is used as a separate symbol in math and science. In mathematics, the kappa curve is named after this letter; the tangents of this curve were first calculated by Isaac Barrow in the 17th century.

## Symbol

### Lowercase (κ)

Mathematics and statistics
Physics
Engineering
• In structural engineering, κ is the ratio of the smaller factored moment to the larger factored moment and is used to calculate the critical elastic moment of an unbraced steel member.
• In electrical engineering, κ is the multiplication factor, a function of the R/X ratio of the equivalent power system network, which is used in calculating the peak short-circuit current of a system fault. κ is also used to denote conductivity, the reciprocal of resistivity, rho.
Biology and biomedical science
Psychology and psychiatry
Economics

### Uppercase (Κ)

History
Mathematics and statistics
Chemistry

## Character encodings

Character information
Preview Κ κ ϰ
Unicode name GREEK CAPITAL LETTER KAPPA GREEK SMALL LETTER KAPPA GREEK KAPPA SYMBOL COPTIC CAPITAL LETTER KAPA COPTIC SMALL LETTER KAPA
Encodings decimal hex dec hex dec hex dec hex dec hex
Unicode 922 U+039A 954 U+03BA 1008 U+03F0 11412 U+2C94 11413 U+2C95
UTF-8 206 154 CE 9A 206 186 CE BA 207 176 CF B0 226 178 148 E2 B2 94 226 178 149 E2 B2 95
Numeric character reference &#922; &#x39A; &#954; &#x3BA; &#1008; &#x3F0; &#11412; &#x2C94; &#11413; &#x2C95;
Named character reference &Kappa; &kappa; &kappav;, &varkappa;
DOS Greek 137 89 161 A1
DOS Greek-2 181 B5 228 E4
Windows 1253 202 CA 234 EA
TeX \kappa
• Mathematical Kappa

Character information
Preview 𝚱 𝛋 𝛞 𝛫 𝜅
Unicode name MATHEMATICAL BOLD
CAPITAL KAPPA
MATHEMATICAL BOLD
SMALL KAPPA
MATHEMATICAL BOLD
KAPPA SYMBOL
MATHEMATICAL ITALIC
CAPITAL KAPPA
MATHEMATICAL ITALIC
SMALL KAPPA
Encodings decimal hex dec hex dec hex dec hex dec hex
Unicode 120497 U+1D6B1 120523 U+1D6CB 120542 U+1D6DE 120555 U+1D6EB 120581 U+1D705
UTF-8 240 157 154 177 F0 9D 9A B1 240 157 155 139 F0 9D 9B 8B 240 157 155 158 F0 9D 9B 9E 240 157 155 171 F0 9D 9B AB 240 157 156 133 F0 9D 9C 85
UTF-16 55349 57009 D835 DEB1 55349 57035 D835 DECB 55349 57054 D835 DEDE 55349 57067 D835 DEEB 55349 57093 D835 DF05
Numeric character reference &#120497; &#x1D6B1; &#120523; &#x1D6CB; &#120542; &#x1D6DE; &#120555; &#x1D6EB; &#120581; &#x1D705;

Character information
Preview 𝜘 𝜥 𝜿 𝝒 𝝟
Unicode name MATHEMATICAL ITALIC
KAPPA SYMBOL
MATHEMATICAL BOLD ITALIC
CAPITAL KAPPA
MATHEMATICAL BOLD ITALIC
SMALL KAPPA
MATHEMATICAL BOLD ITALIC
KAPPA SYMBOL
MATHEMATICAL SANS-SERIF
BOLD CAPITAL KAPPA
Encodings decimal hex dec hex dec hex dec hex dec hex
Unicode 120600 U+1D718 120613 U+1D725 120639 U+1D73F 120658 U+1D752 120671 U+1D75F
UTF-8 240 157 156 152 F0 9D 9C 98 240 157 156 165 F0 9D 9C A5 240 157 156 191 F0 9D 9C BF 240 157 157 146 F0 9D 9D 92 240 157 157 159 F0 9D 9D 9F
UTF-16 55349 57112 D835 DF18 55349 57125 D835 DF25 55349 57151 D835 DF3F 55349 57170 D835 DF52 55349 57183 D835 DF5F
Numeric character reference &#120600; &#x1D718; &#120613; &#x1D725; &#120639; &#x1D73F; &#120658; &#x1D752; &#120671; &#x1D75F;

Character information
Preview 𝝹 𝞌 𝞙 𝞳 𝟆
Unicode name MATHEMATICAL SANS-SERIF
BOLD SMALL KAPPA
MATHEMATICAL SANS-SERIF
BOLD KAPPA SYMBOL
MATHEMATICAL SANS-SERIF
BOLD ITALIC CAPITAL KAPPA
MATHEMATICAL SANS-SERIF
BOLD ITALIC SMALL KAPPA
MATHEMATICAL SANS-SERIF
BOLD ITALIC KAPPA SYMBOL
Encodings decimal hex dec hex dec hex dec hex dec hex
Unicode 120697 U+1D779 120716 U+1D78C 120729 U+1D799 120755 U+1D7B3 120774 U+1D7C6
UTF-8 240 157 157 185 F0 9D 9D B9 240 157 158 140 F0 9D 9E 8C 240 157 158 153 F0 9D 9E 99 240 157 158 179 F0 9D 9E B3 240 157 159 134 F0 9D 9F 86
UTF-16 55349 57209 D835 DF79 55349 57228 D835 DF8C 55349 57241 D835 DF99 55349 57267 D835 DFB3 55349 57286 D835 DFC6
Numeric character reference &#120697; &#x1D779; &#120716; &#x1D78C; &#120729; &#x1D799; &#120755; &#x1D7B3; &#120774; &#x1D7C6;

These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.

## References

1. ^ "kappa". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
2. ^ "University of Hong Kong School of Business" (PDF). HKU.{{cite web}}: CS1 maint: url-status (link)