http://en.wiktionary.org/wiki/significant
significant (comparative more significant, superlative most significant)

1.Signifying something; carrying meaning.
2.Having a covert or hidden meaning
3.Having a noticeable or major effect; notable
That was a very significant step in the right direction.
4.Reasonably large in number or amount5.(statistics) Having a low probability of occurring by chance (for example, having high correlation and thus likely to be related).