English: development brief
Welsh: brîff datblygu
Subject: Cynllunio
English definition: Document providing detailed information to guide developers on the type of development, design and layout constraints and other requirements for a particular, usually substantial, site.
Welsh definition: Dogfen yn rhoi gwybodaeth fanwl yn arweiniad i ddatblygwyr ar y math o gyfyngiadau datblygiad cynllun, dylunwaith a gofynion eraill ar gyfer safle arbennig sydd fel rheol o faint sylweddol.