fax
It's short for "facsimile", because the machine creates a facsimile of the original document.
Of course "fax" is a shortening of "facsimile", so early machines were often called "facsimile machines" and people referred to sending a fax as "sending a facsimile". A couple of other names, are telefax and telecopier. Today, a common kind of machine is a multi-function machine that is a copier/scanner/printer/fax. These are called multi-function machines, multi-function printers, or all-in-one's.
Jon is most often the shortened name for the proper name Jonathan. However, it can be a shortened name for some other proper names including John and Jonas.
None.
The name is spelled Debbie, just as you spelled it, except it has a capital "D". Debbie is a shortened version of Deborah but Debbie is often used as the primary name and not as a shortened name.
full name for fax is facsimile
Ignacio is a Spanish boy's name that is often shortened to Nacho.
The shortened name for oxygen is O2.
Perhaps a facsimile stamp.
Karin is the shortened version of the Swedish name Katherine. It is often associated with the Greek word for "pure."
No the name "Teo" is actually of a Spanish origin. It means "God" and is often the shortened name of names such as "Mateo" and "Teodor".
I'm not sure whether the City of SOWETO, next to Johannesburg, SA qualifies as your answer because, the name seems now to have been permanently, not often, 'shortened.' It was originally SOuthWEst TOwnships, and that got compressed into Soweto.