What does ráthaíocht mean in this "sentence"?
[Actually, I don't know if this would be considered a sentence, but it is one continuous line.]

Fearaimíd romhaibh fáilte, a chairde na páirte
fanaíg lámh linn tráth scéalta is ceoil,
eachtruithe is iontais á n-innsint go binn daoibh,
siansa ár sinnsir ag ráthaíocht go deo.

I understand everything else except for the word ráthaíocht.

Hi, here I understand it to mean 'thriving' or 'prospering'.

An Braonach

_________________
Ultach mé agus Gaeilg Uladh a labhraim go measardha maith!

I agree. I'd interpret it as a variation of rathú.

_________________
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).

Thanks for the help Braonach and Breandán!

If anybody has any other ideas about this, please feel free to let me know.