It's being used as the salutation in a letter, and also in the form of "my name a stóirín"

Thank you for the help!

It's an endearment. Literally it means "my little treasure," but idiomatically it means "my dear/my darling."

Redwolf

Thank you so much!!

The "ín" at the end is like the "ie" of dearie, laddie, lassie etc of the "y" of doggy, mummy, daddy, kitty. It has a sense of being small and friendly.

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A language belongs to its native speakers, and when you speak it, you are a guest in their homes.
If you are not a good guest, you have no right to complain about receiving poor hospitality.

Unless it is caicín (courtesy of Bríd: viewtopic.php?f=28&t=959&p=8879&hilit=caic%C3%ADn#p8879)

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My mum often referred to me as "you little shit!" so I always assumed it was just another "term of endearment".

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Múinteoir Gaeilge - Irish Teacher
My "specialty" is Connemara Irish, particularly Cois Fhairrge dialect, but I can also speak Ulster and Munster Irish with native-level pronunciation.
Is fearr Gaeilge ḃriste ná Béarla cliste, cinnte, aċ i ḃfad níos fearr aríst í Gaeilge ḃinn ḃeo na nGaeltaċtaí.
Gaeilge Chonnacht (GC), go háraid Gaeilge Chois Fhairrge (GCF), Gaeilic Uladh (GU), Gaelainn na Mumhan (GM), agus Gaeilge an Chaighdeáin Oifigiúil (CO).

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