いどこ

See also: いとこ

Japanese

Alternative spellings
何処何所

Etymology

/id͡zuko/ → /idoko/

Shift from いずこ (izuko) of the same meaning.

Continuing the analogy with locative pronouns ここ (koko) and そこ (soko), each having a -o in their initial morae, the medial -zu- changes to -do-. (Can this⁽⁺⁾ etymology be sourced?)

Pronoun

いどこ • (idoko)

(archaic, obsolete) indefinite interrogative pronoun: where, whence, whither, which
- c. 935, Ki no Tsurayuki, Tosa Nikki (Jōhei 5, twenty-ninth day of the first month)
  おもしろき所(ところ)に船(ふね)を寄(よ)せて「ここやいどこ」と問(と)ひければ「土(と)佐(さ)の泊(とまり)」と言(い)ひけり。
  Omoshiroki tokoro ni fune o yosete, “koko ya idoko,” to toikereba, “Tosa-no-tomari” to iikeri.
  As the boat arrived at some fascinating place I asked, “Whither here?” He said, “Tosa Harbor”.
  
  [Note: a manuscript close to the original uses いづこ (izuko) of the same meaning instead of idoko.]
(archaic, obsolete, after a particle) indefinite demonstrative pronoun: anywhere, everywhere, somewhere

Derived terms

どこ (doko, modern form)

Classical Japanese pronouns and demonstratives
	a-/wa- “I, we” (first person)	na-/-ma- “you, ye, thou” (second person)	k- “this” (close to speaker)	s- “that” (close to listener)	a-/ka- “that over there” (far from both)	i-/ta-/nani- “who, what, where, how, when” (interrogative)	ono- “oneself” (reflexive)
Person	あ (a) あれ (are) わ (wa) われ (ware) まろ (maro)	な (na) なれ (nare) なんぢ (nanji) まし (mashi) いまし (imashi) みまし (mimashi) きみ (kimi)	こ (ko) これ (kore)	そ (so) それ (sore)	あ (a) あれ (are) か (ka) かれ (kare)	た (ta) たれ (tare) なにがし (nanigashi)	おの (ono) おのれ (onore)
Thing			こ (ko) これ (kore)	そ (so) それ (sore)	あ (a) あれ (are) か (ka) かれ (kare)	いづれ (izure) なに (nani)
Location			ここ (koko)	そこ (soko)	あしこ (ashiko) かしこ (kashiko)	いづく (izuku) いづこ (izuko) いどこ (idoko) どこ (doko)
Direction			こち (kochi) こなた (konata)	そち (sochi) そなた (sonata)	あち (achi) あなた (anata) かなた (kanata)	いづち (izuchi) いづら (izura) いづかた (izukata)
Manner			か (ka) かく (kaku) かくて (kakute) かう (kō)	さ (sa) さて (sate) しか (shika)		いか (ika)
Time						いつ (itsu)