Glossary
RoHS
RoHS restricts the use of specific hazardous substances, including lead, mercury and certain flame retardants, in electrical and electronic equipment. Both the EU and UK operate their own RoHS regimes, and RoHS compliance normally counts toward the product's CE or UKCA marking.
Why it matters
RoHS applies to components and materials as well as finished products, so it usually needs supplier declarations or testing evidence reaching back into your bill of materials, not just a check on the finished device.