The word 'prefix' is correct and usable in written English.
It is typically used to refer to a letter or group of letters that is added to the beginning of a word in order to modify its meaning. For example: "The prefix 'pre-' means before, so the word 'predict' means to tell about something before it happens."
When Lynn, a transgender woman, contacted her bank to ask them to change her prefix on future correspondence from Mr to Ms, she was surprised at their response.
A touch of intimacy could be added with a prefix.
There is a verb for the English phrase "to get lost in thought", which is made from the verb for "to think", the prefix za meaning behind or beyond, and the reflexive suffix.
If a prefix is required it's required, and you need to think about whether you are going in, out, up, down, towards, away from, around, or on the way to somewhere else.
Astute readers will notice that I didn't give Mr Warne his now traditional prefix of "world's greatest" spinner above.
The armed forces are to gain the prefix "Bolivarian"—a reference both to Simón Bolívar, South America's independence hero, and to the president's own movement.
To see why, suppose it was not prefix-free.
The change is the natural one: we appeal, not to the plain complexity of a sequence in defining its randomness, but the so-called prefix-free complexity (Downey and Hirschfeldt 2010: §2.5ff; Dasgupta forthcoming: §8).
As before, we can show there exist better decompression algorithms than this one, and indeed, that there exists a universal prefix-free decompression algorithm u, such that for every other algorithm m there is a k such that Ku ≤ Km + k, for all σ (Downey and Hirschfeldt 2010: §2.5).
Prefix-free encodings are useful for a number of practical purposes, and they turn out to be useful in defining randomness also.
A good example of an encoding like this is the encoding of telephone numbers: the telephone exchange can, on input of a string of digits that it recognises, immediately connect you; once an acceptable code from a prefix-free set has been input, no other acceptable code can follow it.
