[proxy_user]

This etymology is questionable. The word is 17th-century school slang. Academics would almost certainly have preserved the 'h' of khronos.

[syriacus]

http://laudatortemporisacti.blogspot.com/2005_10_01_laudatortemporisacti_archive.html

But the spelling of the OED's first citation (from Pepys' Diary, May 30, 1665) tends to support the Greek origin:

Jack Cole, my old school-fellow..who was a great chrony of mine.