THE Nidd, one of the north's more picturesque rivers, runs close to Harrogate before joining the Ouse just outside York. But what does that simple syllable mean?

Well, as is always the case with river names, it is necessary, if you want to get at the meaning, to first answer another question: what language does the word Nidd come from?

Now in Britain there are rivers named in Norman French (though very few), in Norse - the language of the Vikings, in Anglo- Saxon and also in Celtic.

And, in fact, Nidd comes from that last and earliest stratum of recorded British languages. It is Celtic and this means that it may be two or three thousand years old; to get the full sense of this you must remember that most town or village names are a pathetic thousand or thirteen hundred years old - the Nidd then virtually has stalactites hanging off it.

The river's meaning is, however, a little less dramatic: Nidd meant simply the flowing one'.

Now in case this is a disappointment, it should be remembered that river names in Britain are generally tedious: we have waterways called the fast one' (the Tame), the watery one' (the Goyt) and the valleyed one' (the Colne).

And a series of rivers across Western Europe have the same root as the Nidd, even if twisted out of shape by the centuries, for modern pronunciation and spelling are all different.

The Nidd's cousins include, and this list is far from exhaustive, the Neath in Glamorgan, the Nethe in Belgium, another Nethe in Germany where there is also a Nidde and a Niede.

* Simon Young is a historian and author of AD500.