This is just a wild stab at it.  It sounds like "aggregate substance".  The
thing that most resembles that expression in my opinion is "Compound".
It's just a guess.

At 01:49 PM 2/24/99 +0100, you wrote:
>Hi all
>
>Could someone give me the English expression to describe in what state (
>solid, liquid, gas ) a substance is. In German we call it Aggregatszustand
>( just a hint for those with German background ). Thanks a lot.
>
>Best regards
>
>Guenter
>
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