When is a prefix not a prefix?

[Rhubarb]

dd has homework based on prefixes. However some of the words they are claiming are prefixes, I'm not too sure about. To my mind, a prefix is something you add to the beginning of a word that makes another, different word. But that word has to be there in its own right first.

So for example misbehave is fine because you are adding it to the word 'behave'. But how about 'exterior' and 'explode'? If you take away the prefixes, then the word does not exist. However you can change the words to 'implode' and 'interior' - is this enough to make them prefixes?

Anyone?

The Oxford dictionary defines a prefix as an element placed a the beginning of a WORD to adjust or quantify its meaning ....(e.g. ex, non, re) ...

So, in answer, I think it is ...

I think you're right- just searched through my grammar books (am TEFL teacher ) and vaguely remember some rule similar to what you said, it is that the "ex" in explode looks like the "ex" of "ex-husband" for example, but to be a prefix is has to be added to the root word without the root word having to change form/spelling and also with the root word having a meaning of its own without the prefix...
I'm going to dig out the grammar bible and have a proper look....back in a mo...

Technically, it's the inter and the exter which are the prefixes (think, was looking up defintion to see if "terior" was a word)

Not helping you really but there are lots of examples of this aren't there - uncouth, inept.

I thought I was definitely right when I read the BBC's definition that a prefix is added to a root word and the root word has to stand as a word on its own.

Until I came across this which has 'expire' as an example of ex being used as a prefix.

It's very confusing!

I presume the expire example comes from its Latin root (I don't know Latin, but in Italian there is respirare - to breathe- so that will be the connection there...
I think generally speaking, the definition you give is correct...a prefix can be added to a root word and the root word needs to be able to stand on its own....It's establishing sometimes that some words don't look like they can stand alone...Like "plode" to me doesn't at all look like it is morphologically (meaningful unit) OK on its own..but maybe it's a latin root....(feasible, as there is esplodere in Italian....)

Right, upon further investigation, there seem to be many prefixes that, when you take away the prefix the root word does not make sense on its own.

Who said English was simple eh?

Yes, I think that the Latin ones are problematic, as they've been loaned into English as they stand, so the stems that remain don't make sense in English, though they do in Latin. But Ask Oxford does use the same examples: A prefix is an element placed at the beginning of a word to adjust or qualify its meaning (e.g. ex-, non-, re-).

I've lost my really really good grammar book somehow. If I find out more I shall return.

I think this is one of the times where you explain the rule, and then explain all the other cases where the rule doesn't quite work.

Prefixes work exactly as described. But some of our words are borrowed, so the root isn't a word in English. But it's still worth looking at the prefix, because it can help you work out what the word means.

Thanks. It is one of 'those' isn't it? English is infuriating at times because you come up with a rule and then find out that there are hundreds of exceptions to the rule which makes the rule bloody well useless at times!

fuzzy grammar, Rhubs. there's a whole subject of study on it!

Apparently explode comes from the latin ex- (out) + plaudere (to clap) and originally meant 'to drive out by clapping, hiss (a player) off the stage.'

Exterior is derived from the Latin exter-us (outside).

We had a similiar homework at the beginning of April,and it irritated me so much that it forced me to de-lurk and post for the first time! Ds had suffixes too,including 'enough'(suffix 'ough').Anyway,the problem seemed to be that some of these words can be broken down to prefixes and root words ,but in quite a few of them this only works in Latin...bit complex for Yr 4!Personally I think this should be taught in a different way,and someone did suggest that the actual homework is on spelling patterns,mis-named.
Oh dear,now I'm irritated again