入る

From older 這い入る (haiiru, older pronunciation faiiru), itself a compound of 這い (“to crawl”, continuative form) +‎ 入る (iru, “to enter, to go in”).^[1][2][3][4]

• /faiiru/ → /fairu/ → /hairu/

This shortened hairu form is first attested from the early 1200s.^[1]

• (Tokyo) はいる (Atamadaka – )^[3][4][5][1]
• IPA^(key):

• (Kyoto) はいる  (Teiki – )^[1]

入(はい)る • (hairu) intransitive godan (stem 入(はい)り (hairi), past 入(はい)った (haitta))

1. to enter, go into, get into a place or a thing

   お風(ふ)呂(ろ)に入(はい)る

   o-furo ni hairu

   get in the bath

   対(たい)策(さく)の検(けん)討(とう)に入(はい)る

   taisaku no kentō ni hairu

   enter countermeasure discussion → start discussing plans for countermeasures

   亀(き)裂(れつ)が入(はい)ったタイヤ

   kiretsu ga haitta taiya

   tire with cracks that have entered it → a cracked tire

   Antonym: 出る (deru, “to leave, to exit, to go out”)

   1. to join a group or organization
2. to be contained (in), to be included (in)
   • 2007, 新時代日漢辭典 / 新时代日汉辞典 (Xīn Shídài Rì-hàn Cídiǎn), 1st edition, 大新書局 / 大新书局 (Dàxīn Shūjú), →ISBN:

     旅(りょ)費(ひ)には朝(あさ)晩(ばん)の食(しょく)事(じ)代(だい)も入(はい)っています。

     Ryohi ni wa asaban no shokujidai mo haitte imasu.

     The morning and evening meal plans are also included in the travel expenses.

3. to be a member of a group, set, category

   先(せん)生(せい)、バナナはおやつに入(はい)りますか？

   Sensei, banana wa o-yatsu ni hairimasu ka?

   Teacher, do bananas count as snacks? (rhetorical question in popular culture)

4. to be in a container, building, etc.
   • 2007, 新時代日漢辭典 / 新时代日汉辞典 (Xīn Shídài Rì-hàn Cídiǎn), 1st edition, 大新書局 / 大新书局 (Dàxīn Shūjú), →ISBN:

     この部(へ)屋(や)には百(ひゃく)人(にん)入(はい)れる。

     Kono heya ni wa hyaku-nin haireru.

     In this room, one hundred people can enter → This room can contain a hundred people.

5. to enter a period of time

   令(れい)和(わ)時(じ)代(だい)に入(はい)る、晩(ばん)に入(はい)る

   Reiwa jidai ni hairu, ban ni hairu

   to enter the Reiwa era, to enter into evening

6. to be included and available for use

   ノートに罫(けい)が入(はい)った

   nōto ni kei ga haitta

   in the notebook, lines are in it → the notebook has lines in it → the notebook has ruled pages

• 手(て)に入(はい)る (te ni hairu)

From Old Japanese. First attested in the Man'yōshū of 759.^[6]

For the development of the to be necessary sense, consider the English phrase to come into it in the sense to be a factor in something. In modern usage, this particular sense is more commonly spelled as 要る.

• (Tokyo) いる (Heiban – )^[3][4][5][6]
• IPA^(key):

• (Kyoto) いる  (Kōki – )^[6]

入(い)る • (iru) intransitive godan (stem 入(い)り (iri), past 入(い)った (itta))

1. to go in; to come in
   • 2007, 新時代日漢辭典 / 新时代日汉辞典 (Xīn Shídài Rì-hàn Cídiǎn), 1st edition, 大新書局 / 大新书局 (Dàxīn Shūjú), →ISBN:

     俺(おれ)の耳(みみ)に水(みず)が入(い)った

     Ore no mimi ni mizu ga itta

     Water went in my ear

2. 要る: to be necessary, to be required

   お金(かね)がいるね

   okane ga iru ne

   money comes into it → money is needed → you'll need money

• Mostly confined to fixed expressions and idioms.

• 気(き)に入(い)る (ki ni iru)
• 手(て)に入(い)る (te ni iru)

• 恐(おそ)れ入(い)る (osoreiru)

入(い)る • (iru) transitive ^†nidan

1. to put something into something else

• 入(い)れる (ireru, modern form)

• 2002, Ineko Kondō; Fumi Takano; Mary E Althaus; et. al., Shogakukan Progressive Japanese-English Dictionary, Third Edition, Tokyo: Shōgakukan, →ISBN.