入る

Etymology 1
From older, itself a compound of.



This shortened hairu form is first attested from the early 1200s.

Verb

 * 1)  to enter, go into, get into a place or a thing
 * 2)  to join a group or organization
 * 3)  to be contained (in), to be included (in)
 * 4) to be a member of a group, set, category
 * 5) to be in a container, building, etc.
 * 6)  to enter a period of time
 * 7)  to be included and available for use
 * 1) to be a member of a group, set, category
 * 2) to be in a container, building, etc.
 * 3)  to enter a period of time
 * 4)  to be included and available for use
 * 1) to be in a container, building, etc.
 * 2)  to enter a period of time
 * 3)  to be included and available for use
 * 1)  to enter a period of time
 * 2)  to be included and available for use
 * 1)  to be included and available for use

Etymology 2
From. First attested in the  of 759.

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

Verb

 * 1)  to go in; to come in
 * 2)   to be necessary, to be required
 * 1)   to be necessary, to be required
 * 1)   to be necessary, to be required

Usage notes

 * Mostly confined to fixed expressions and idioms.

Verb

 * 1) to put something into something else