The unexpected discovery that I made is about this word. I was reading in A Siamese-Dictionary, 1892, by E. B. Michell and found this:
กอปี้ (kawpee) [Engl.] copy; สมุด--- copy-bookI had no idea this word has been around in Thai for so long. This shows that its original borrowed sense was to make a handwritten copy. The native word for this is ลอก or คัดลอก. ก๊อปปี้ retains this sense today, along with newer more technologically advanced meanings.
ซี [sii] = to photocopy. Clipped from 'Xerox'. The full name,
Another interesting thing is that you can use either ก๊อปปี้ or ซีรอกซ์ with the verb ถ่าย: ถ่ายซีรอกซ์ or ถ่ายก๊อปปี้ (the formal Thai is ถ่ายสำเนา), but the clipped forms are usually used as verbs by themselves. ซี is equivalent to ถ่ายซีรอกซ์, and ก๊อป is equivalent to ถ่ายก๊อปปี้.