Lock

n.

Heard in Monaghan, Derry, Westmeath, Offaly, Galway, Donegal, Tyrone and Roscommon

A large quantity or generous abundance of something.

In use

Are ye comin' out with us for a lock of pints later on?

Posh English

Would you care to accompany us for a generous round of tankards later this evening?

Same phrase, other counties