What do the acronyms AOF and RDB stand for in Redis?

I would like to make an update @Tague's answer (for RDB) and also adding a basic info for each.
Both of these are options if one has to choose persistence for Redis data.

RDB is for Redis Database Backup file.
RDB file is a dump of all user data stored in an internal, compressed serialization format at a particular timestamp which is used for point-in-time recovery (recovery from a timestamp).

AOF stands for Append Only File.
AOF is actually a persistence technique in which an RDB file is generated once and all the data is appended to it as it comes.

AOF stands for Append Only File. It's the change-log style persistent format.

RDB is for Redis Database File. It's the snapshot style persistence format.