That operates to produce an effect.
Any of a class of behaviors that produce consequences by operating (i.e., acting) upon the environment.
An operative person or thing.
Having a noticeable or major effect.
Reasonably large in number or amount.
Having a low probability of occurring by chance (for example, having high correlation and thus likely to be related).
Having a covert or hidden meaning.
Signifying something; carrying meaning.
That which has significance; a sign; a token; a symbol.