Also the leaflets are even numbered, unlike ailanthus which has odd numbers with one at the end.

More likely Chinese Pistache...a commonly planted very drought tolerant tree in urban areas where hardy

By any chance the tree above is from this nut? I see these nuts frequently around here and germinating and producing similar leaves.

Its a quarter near it for size comparison:

Agree with smivies.

Are the nuts edible?

The nut pictured is somewhat out of focus but certainly could be a walnut. Postache has different fruit. Were there green or dark brown husks in the same area? What does it look like when cracked open?

I was hoping to save that nut to plant, if its an edible one. But just found out another seedling lurking around in one of the pots, squirrels must have put the nut in there. Are you guys sure its Chinese pistache? The nut doesn't look like came from such tree

Anybody :-) ?

Sowmya, things are getting confused. Your latest plant is clearly a nut of some kind but that doesn't mean the previous one is the same nor yet the original one from 2016. To me the latest leaf doesn't look like the very first plant's leaf. The edges are more serrated and the leaflets are slightly staggered rather than directly opposite. And, although it's hard to see the ends of the leaves in no.1, it doesn't appear to have a terminal leaflet, whereas your latest one does.

I thought both are same, let me examine more closely in day light tomorrow. But any idea of the nut from recent pics?

Both pictured nuts appear to be walnuts.