Full backup
A complete copy of all selected data, independent of any other backup.
Full backups restore fastest and simplest because everything needed sits in one set, with no chain to reassemble. They also take the longest to run and consume the most storage.
Most schedules combine a periodic full with incrementals in between, balancing backup window against restore complexity.
Where this comes up
Full backup sits inside our backup and disaster recovery work. If you are trying to work out what this means for your own environment rather than in the abstract, that is the page worth reading next, and a short call will get you a straight answer faster than either.