In Irish English, the word grand has the familiar meanings: impressive, magnificent, high-ranking, very large, etc. – size being etymologically salient – but its most common use is in the dialectal sense ‘OK, fine, satisfactory’. As such it often appears in brief, affirmative replies:
How’s it going?
Grand, thanks.Was the sea cold?
It was grand.How did the interview go?
I got on grand.I’ll pick you up in an hour.
Grand.I’m sorry about that.
Ah no, you’re grand. [Don’t worry about it.]
This use of grand is so routine and prevalent in Ireland that it’s virtually a state of mind (and hence popular in T-shirt designs and the like). This comes in handy for understatement in injurious situations:
Posted by Stan Carey 
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