keep vs rein

keep and rein both are nouns.

Word	Noun	Adjective	Verb	Adverb
keep	Yes	No	Yes	No
rein	Yes	No	Yes	No

As verbs, rein is a hyponym of keep; that is, rein is a word with a more specific, narrower meaning than keep:

keep (noun)	rein (noun)
the main tower within the walls of a medieval castle or fortress	one of a pair of long straps (usually connected to the bit or the headpiece) used to control a horse
a cell in a jail or prison	any means of control
the financial means whereby one lives

keep (verb)	rein (verb)
prevent (food) from rotting	keep in check
prevent the action or expression of	stop or slow up one's horse or oneself by or as if by pulling the reins
stick to correctly or closely	stop or check by or as if by a pull at the reins
maintain by writing regular records	control and direct with or as if by reins
supply with necessities and support
hold and prevent from leaving
retain possession of
look after; be the keeper of; have charge of
retain rights to
maintain for use and service
have as a supply
store or keep customarily
stop (someone or something) from doing something or being in a certain state
allow to remain in a place or position or maintain a property or feature
conform one's action or practice to
behave as expected during of holidays or rites
cause to continue in a certain state, position, or activity
supply with room and board
maintain in safety from injury, harm, or danger
fail to spoil or rot
continue a certain state, condition, or activity
to rear