This article is from the Puzzles FAQ, by Chris Cole email@example.com and Matthew Daly firstname.lastname@example.org with numerous contributions by others.
What are some redundant terms that occur frequently (like "ABM missile")?
11.5% APR (although "APR" means that interest is charged on the balance only)
AMOCO Oil Co.
APL programming language
CNN news network
DOS operating system
Geirangerfjorden (Fjord Fjord Fjord)
Mount Fujiyama (Mount Mountain)
NFS File System
RAM (or ROM) memory
Rio Grande River (Big River River)
Ruidoso River (Noisy River River)
SALT talks or SALT treaty
START talks or START treaty
The La Brea Tar Pits (The The Tar Tar Pits)
The Los Altos Hills (The The Hills Hills)
floccinoccinihlipilification (from 4 latin words meaning "nothing")
the hoi polloi (the the many)
hot water heater