Sr.

13:08 Sep 9, 2015 

I wonder if there's a clue in the L-R orientation of the text (Arabic is written R to L)?

The columns in your table curiously seem to be in the wrong order: Home address on the left, followed by Occupation, then Nationality, name, and finally this Sr.
If we were creating this form in EN, we'd probably start with 'Title' on the left, then Name, Nationality, Occupation, and lastly Home Address.

Clutching at straws, but it might be an avenue for further research.

Maybe you could find someone among our Arabic colleagues who could shed some light?

13:02 Sep 9, 2015 

Ha, I've just noticed that You mentioned the "signature". This looks like the space available is just enough to put some number (maybe one digit only), or a simplified signature - initials only.

12:25 Sep 9, 2015 

This doesn't appear to be a standard EN usage, and I see this document originates from a country where EN is not the official language.

I think it is going to be impossible to guess this without a great deal more of the wider context; it is possible that a phone call to the company concerned would be the simplest and quickest way of resolving this issue.

It did just cross my mind that it might be a non-standard abbreviaition for 'signature', or (in view of the small space allowed) possibly intended for 'initials' — but I think this is probably some error induced by a writer coming from an Arab background and trying to reproduce in EN something that is in fact specific to their own culture; it might, for example, have been meant to indicate 'Title', as in Mr/Mrs/Ms etc.