Is fallow a prefix?

The word 'prefix' does contain a prefix; it is made up from the Latin praefixus (fix in front [of]) + figere (to fasten, to fix), so the 'pre-' part of the word is a prefix.The word 'prefix' itself...

The prefix for prefix is pre because its before and fix is the word so the prefix for prefix is pre.

prefix is a prefix

In medical terminology a suffix such a otomy means cut. Therefore if I write the word myringotomy it means the cutting of the eardrum. Opsy means poke a hole or look through a hole: biopsy ectomy...

Of course, it would be pre- because pre- means the word before the actual word and the word before the actual word in prefix is pre-.