Definition from Wiktionary, the free dictionary
See also Yah
Etymology 1 
An alternative pronunciation, akin to yeah.
yah (not comparable)
- (UK, India, South Africa) Yes.
- Yah, we did go along but it turned out the wedding was a load of nonsense.
Etymology 2 
From the pronunciation of “yes” which such people use.
yah (plural yahs)
Variant of yuh (“here”).
- father (male parent)