A tremolo is a very fast repetition of a single note to produce a shivering, shaking effect.

When politicians use the phrase ‘terminological inexactitude’, they usually just mean that someone is telling porkies.

When it comes to musical terms, however, it’s often an accurate diagnosis. ‘Tremolo’ (or is it ‘tremolando’?) is a first-rate example. The Italian word means ‘trembling, quivering’.

But what kind of trembling or quivering? Trying to pin down what composers meant by ‘tremolo’, at least until the mid-19th century, may lead to quivering of another kind.

In today’s usage, ‘tremolo’ is not to be confused with ‘vibrato’, where the note trembles by moving up and down. However, in Monteverdi or Purcell’s time this seems to have been exactly what many thought of as ‘tremolo’ – especially when applied to the voice.

In modern parlance, tremolo/tremolando is a rapid repetition on one note – so rapid that if it’s played by a string ensemble it blurs into shimmering haze. The mysterious nebula-like sounds that begin around half of Bruckner’s symphonies are the classic example.

But when you see the same thing in 18th- or early 19th-century scores, did the composers have something similar in mind? When Vivaldi indicated rapid demisemiquavers in ‘Winter’ from The Four Seasons – to illustrate ‘a horrid wind’ and ‘chattering teeth’ – he must have known that some blurring would probably take place.

Yet the way this is written suggests that, given an ideal world full of ideal musicians, each fleeting note should be measured out precisely. You get a similar feeling score-reading the magical hushed tremolo passage in the slow movement of Haydn’s G minor Quartet, Op. 74, No. 1 – but you rarely hear it played that way.

And what of the beginning of Beethoven’s Ninth Symphony? In some older recordings what you hear is a Brucknerian romantic mist. But what Beethoven writes is sextuplet semiquavers; only later, at the climax of the movement, do you get demisemiquavers – ie faster repetitions on one note.

If Beethoven, of all composers, writes something in two different ways, then he almost certainly wants it to sound different. Bruckner is said to have got his tremolo/nebula idea from Beethoven’s Ninth, yet the likelihood is that Beethoven had something much more tense and precise in mind.

Did Bruckner simply hear a bad performance? If so, it just shows how fertile misunderstanding can be.

This article was first published in the November 2011 issue of BBC Music Magazine