(In British use at least)
An unofficial word, used in an enquiring sense. A request for afermation of an opinion just stated. Regional variations do exist, Westcountry pronuciation would be "Aie?" while South East might be "eh?"
eg.
"That's OK...ay?"
"This alright...ay?"
"Nearly finished this little writeup...ay?"
"You got my meaning now...ay?"