Beuth Verlag publishes standards, and on the few occasions I would have liked to use one, they were too expensive for me.

Now the publisher has put DIN terminology online free of charge.

The first site gives the translations of terms used in norms, the second gives more information such as definitions, notes and examples, but it requires registration:

DIN-TERM online
DIN-TERMinologieportal (registration needed)

Thanks, Marc!