Going back to my music college days, the term hemiola was applied to a syncopation across a couple of bars, so in a two bar phrase that would have had say 8 beats, the beats would be regrouped to maybe contain 6. It wasn't always a 3 against 2, it depended on what the composer wanted. It was just a drawing out or speeding up of the beat. Making more or less than would be normal in a phrase.
Er, that didn't make sense did it? I remember it happening a lot in Beethoven, >tingles< was quite a spine chilling effect in some of his symphonies. >sigh<