いとこ

⟨ito₁ko₁⟩ → */itʷokʷo/ → /itoko/

Cognate with and by extension of Old Japanese いとこ (ito₁ko₁, “close, familial, or beloved person”).^[1][2] Ultimately from Proto-Japonic *itoko.

First attested in the Kojiki of 712 CE.^[1]

• (Tokyo) いとこ [ìtóꜜkò] (Nakadaka – [2])^[2][3][1]
• IPA^(key): [ito̞ko̞]

• (Kyoto) い​とこ [íꜜtòkò] (Kōki)^[1]

いとこ • (itoko) 

1. one's cousin (may be spelled in kanji to indicate the gender and relationship with the person in question):
   1. 従兄弟: a male cousin
      1. 従兄: an older male cousin
      2. 従弟: a younger male cousin
   2. 従姉妹: a female cousin
      1. 従姉: an older female cousin
      2. 従妹: a younger female cousin
   3. 従兄妹: an older male cousin and younger female cousin
   4. 従姉弟: an older female cousin and younger male cousin

いとこ • (Itoko) 

1. いとこ, 伊杜子, 委登子, 伊斗子, 従姉弟, 意杜子, 伊東子, 伊登子, 以杜子, 委杜子, 委斗子, 依杜子, 衣杜子, 衣登子, 惟杜子, 伊十子, 似登子, 生都子, イト子, 惟登子, いと子, 維斗子, 以都子, 依都子, 衣都子, 維都子, 意都子, 惟都子, 伊都子, 委都子, 系子, 純子, 紀子, 順子, 文子, 最子, 絲子, 愛子, 綸子: a female given name
2. 伊刀古: (obsolete) a male given name

For quotations using this term, see Citations:いとこ.

• はとこ (hatoko, “second cousin”)

Ultimately from Proto-Japonic *itoko.

From stem ito- cognate with modern 愛しい (itoshii, “dear, precious”) +‎ 子 (ko₁, “child”).^[1]

いとこ (ito₁ko₁)

1. a person close, familial, or otherwise beloved (to the speaker, etc.)
2. (by extension) one's cousin

For quotations using this term, see Citations:いとこ.

• Japanese:
  • 愛子 (itoko, “beloved”), in modern Japanese dictionaries
  • いとこ (itoko, “cousin”)