Dyadic kinship terms are kinship terms in a few languages that express the relationship between individuals as they relate one to the other. In English, there are a few set phrases for such situations, such as "they are father and son", but there is not a single dyadic term that can be used the way "they are cousins" can; even the latter is not truly dyadic, as it does not necessarily mean that they are cousins to each other. The few, and uncommon, English dyadic terms involve in-laws

In-Laws

In-Laws is an American situation comedy that aired on NBC from September 2002 until January 2003. The series starred Bonnie Somerville, Jean Smart, Elon Gold, and Dennis Farina....

: co-mothers-in-law, co-fathers-in-law, co-brothers-in-law, co-sisters-in-law, co-grandmothers, and co-grandfathers.

Examples of dyadic terms for blood kin include Kayardild

Kayardild language

-Further reading:* Evans, Nicholas. 1988. Odd topic marking in Kayardild. In Peter Austin, ed., Complex sentence constructions in Australian Languages. Amsterdam: John Benjamins. pp. 219–266....

 (Australian) ngamathu-ngarrba "mother and child", derived from ngamathu "mother", and kularrin-ngarrba "brother and sister", from kularrin "cross-sibling", with the dyadic suffix -ngarrba. Not all such terms are derived; the Ok

Ok languages

The Ok languages are a family of a score of clearly related Trans–New Guinea languages spoken in a contiguous area of eastern Irian Jaya and western Papua New Guinea...

 language Mian

Mian language

Mian is an Ok language spoken in the Telefomin district of the Sandaun province in Papua New Guinea by the Mian people. It has some 3,500 speakers spread across two dialects: West Mian with approximately 1,000 speakers in around Yapsiei and East Mian with approximately 2,500 speakers in and around...

 has a single unanalysable root lum for "father and child".

Dyadic blood kin terms are absent from Indo-European languages

Indo-European languages

The Indo-European languages are a family of several hundred related languages and dialects, including most major current languages of Europe, the Iranian plateau, and South Asia and also historically predominant in Anatolia...

 with the exception of Icelandic

Icelandic language

Icelandic is a North Germanic language, the main language of Iceland. Its closest relative is Faroese.Icelandic is an Indo-European language belonging to the North Germanic or Nordic branch of the Germanic languages. Historically, it was the westernmost of the Indo-European languages prior to the...

 and Faroese

Faroese language

Faroese , is an Insular Nordic language spoken by 48,000 people in the Faroe Islands and about 25,000 Faroese people in Denmark and elsewhere...

, which have the terms feðgar "father and son", feðgin "father and daughter", mæðgin "mother and son", mæðgur "mother and daughter".

The languages which have such terms are concentrated in the western Pacific. There are at least ten in New Guinea, including Oksapmin

Oksapmin language

Oksapmin is a Trans–New Guinea language spoken in Telefomin District, Sandaun, Papua New Guinea. It has been influenced by the Ok languages , and the similarities with those languages were attributed to borrowing in the classifications of both Stephen Wurm and Malcolm Ross , where Oksapmin was...

, Menya, and the Ok languages; fifteen or more Austronesian languages

Austronesian languages

The Austronesian languages are a language family widely dispersed throughout the islands of Southeast Asia and the Pacific, with a few members spoken on continental Asia that are spoken by about 386 million people. It is on par with Indo-European, Niger-Congo, Afroasiatic and Uralic as one of the...

, from Taiwan to New Caledonia; and at least sixty in Australia, such as Kayardild above. There are sporadic examples in Northern Eurasia, including a few Turkic

Turkic languages

The Turkic languages constitute a language family of at least thirty five languages, spoken by Turkic peoples across a vast area from Eastern Europe and the Mediterranean to Siberia and Western China, and are considered to be part of the proposed Altaic language family.Turkic languages are spoken...

 and Uralic

Uralic languages

The Uralic languages constitute a language family of some three dozen languages spoken by approximately 25 million people. The healthiest Uralic languages in terms of the number of native speakers are Hungarian, Finnish, Estonian, Mari and Udmurt...

 languages, Yukaghir, and Ainu

Ainu language

Ainu is one of the Ainu languages, spoken by members of the Ainu ethnic group on the northern Japanese island of Hokkaidō....

; depending on definitions, the Yi languages of Southeast Asia may also be said to have such terms. Elsewhere they are rare, or at least haven't been described. Known languages include Athabaskan (Koyukon

Koyukon language

Koyukon is an Athabaskan language spoken along the Koyukuk and middle Yukon River in western interior Alaska. It has about 300 speakers - generally older adults bilingual in English - from an ethnic population of 2,300....

 and Carrier

Carrier language

The Carrier language is a Northern Athabaskan language. It is named after the Dakelh people, a First Nations people of the Central Interior of British Columbia, Canada, for whom Carrier is the usual English name. People who are referred to as Carrier speak two related languages. One,...

), Pomo

Pomoan languages

Pomoan is a family of endangered languages spoken in northern California by the Pomo people on the Pacific Coast. According to the 2000 census, there are 255 speakers of the languages...

, and Southern Paiute in North America, Quechua and Cariban (Tiriyo

Tiriyó language

The Tiriyó language , is spoken by approximately 2,000 people living in several villages on both sides of the Brazil-Suriname border in Northern Amazonia. It is a relatively healthy language, learned by all children as their mother tongue and actively used in all areas of life by its speakers...

) in South America, Adyghe

Adyghe language

Adyghe language , also known as West Circassian , is one of the two official languages of the Republic of Adygea in the Russian Federation, the other being Russian. It is spoken by various tribes of the Adyghe people: Abzekh, Adamey, Bzhedugh; Hatukuay, Kemirgoy, Makhosh; Natekuay, Shapsigh; Zhane,...

 in the Caucasus, and Khoe

Khoe languages

The Khoe languages are the largest of the non-Bantu language families indigenous to southern Africa. They are often considered to be a branch of a suspected Khoisan language family, and are known as Central Khoisan in that scenario. The nearest relative of the Khoe family is the extinct and poorly...

 (Kxoe

Kxoe language

Khwe Kxoe is a dialect continuum of the Khoe family of Namibia, Angola, Botswana, South Africa, and small parts of Zambia, with some 11,000 speakers. It is learned locally as a second language in Namibia, but the language is being lost in Botswana as speakers shift to Tswana, under threat of...

, Gǀwi) in southern Africa.