Ever since the genre called hardstyle submerged out of other genres like hardtrance somewhere around the year 2000, it has been changing rapidly, often referred to as 'the evolution of style'. Around 2005, the hardstyle enthusiasts needed a term for the hardstyle music from the period 2000-2004. It was simply called 'early hardstyle'. The genre kept evolving and so, around 2006, a new kind of sound started taking over the scene. It was the somewhat harder sound with kicks similar to those used in the hardcore house/gabber tracks. Another feature of the sound is the so-called 'pitchkick': when the kicks are being pitched in such a way that they are in harmony with the melody. This sound, that anno 2009 has totally taken over the hardstyle scene, is referred to with the term nu-style.
Besides that, the terms nu-style, new-style, nu-sound (etcetera) may also be referring to new variations of other genres than hardstyle. For example, when the sound of the hardcore house changed around 2000, the new sound was sometimes called nu-hardcore. .
