[NTG-context] Spacing after defined word: beginner's question

This must be a beginner's question, but I can't find the answer to it in the manuals... Take this ConTeXt source: -- \def\Acme{% {\ss\sc ACME}} Welcome from \Acme. \Acme make fine products. -- When this is made into a PDF, it looks like this: -- Welcome from ACME. ACMEmake fine products. -- - because I didn't have a space in the definition, I don't get a space in the second sentence, but the period didn't interfere with the execution of the first occurrence. But if I put a space in the definition after the 'E', I get this: -- Welcome from ACME . ACME make fine products. -- - and there's a space after the first 'E', which I don't want, even though there is now a space after the second... What am I doing wrong?