Cite يستشهد بقول أو بمثال
is a verb meaning to quote as an authority or example.
Sight اسم بمعنى مشهد أو منظر
is a noun meaning the ability to see or something that is seen.
Site اسم و تعنى المكان
is a noun meaning a place or setting of something
In a good essay, it is important to cite expert opinion.
In his old age he had poor sight.
This would be a good site for a new golf course