Diffiniadau — English
- Physics & Chemistry A group of objects related by linearly varying successive differences in form or configuration: a radioactive decay series; the paraffin alkane series.
- Geology A group of rock formations closely related in time of origin and distinct as a group from other formations.
- A succession of usually continuously numbered issues or volumes of a publication, published with related authors or subjects and similar formats.
- A succession of regularly aired television programs, each one of which is complete in and of itself.