You should always check with your ‘Local Authority’ (Local Government) prior to any proposed building works, as in the UK they are the ones who approve Building Regulations and grant Planning Permission.
However, in answer to your specific question, in accordance with advice given on the UK’s Planning Portal, the conservatory is a generic term to describe traditional conservatories, orangeries and glazed extensions; and the Portal goes onto explain that the modern trend is to replace paneled roofs with solid roofs to provide more usable space all year round.
The conservatory we’ve built is strictly an orangery e.g. less glazing on the walls and roof than a traditional conservatory e.g. a solid roof with skylights.
The UK Planning Portal is an Official website that works with all Local Authorities across the UK to help simply Planning Advice and the Planning Process for the public: https://www.planningportal.co.uk/