If you mean part of a horses accessories, then Rein is a noun
... 'rein und raus'.
"De Rein" does not have a specific meaning in English. It could be a name or a phrase in another language.
Rein Liblic's birth name is Liblic, Rein Igorevich.
Rein Strikwerda was born in 1930.
It basically means Good Luck!
what are free rein leaders
The homonym for rein is rain.
Rein Otsason died in 2004.
the Tudors rein was between 1585 and 1603
Martin Rein died in 2010.
Rein is a noun and a verb.