Didn't you check the in-game Civilopedia? I thought I covered it in there! (as I do with all my new units)
A "
Pre-dreadnought" battleship is the general term for all of the types of sea going battleships built between the mid-1890s and 1905. Pre-dreadnoughts replaced the ironclad warships of the 1870s and 1880s. Built from steel, and protected by hardened steel armor, pre-dreadnought battleships carried a main battery of very heavy guns in turrets supported by one or more secondary batteries of lighter weapons. They were powered by coal-fueled triple-expansion steam engines.
Obviously the term "Pre-Dreadnought" was not used at the time, because there were no dreadnoughts to "Pre". The term is a reverse-terminology applied after the fact, but commonly accepted as an actual definition of a ship class/specification.
The term "Battleship" is a very, VERY loose term for a type of warship... as countless ships across over a century of naval warfare have all been called "Battleships" at one point or another. The Age of the Ironclad is more-or-less when the term first started to be used, and (at the time) some ships were simply called "Battleships"... same thing during the time of the Pre-Dreadnoughts... they too were refered to as "Battleships"... so-in WWI, once again... modern ships of the time were called "Battleships"... and of course, in WWII... "Battleships" once again was a term used.
Sure, I could call Pre-Dreadnoughts "Early Battleships"... but that term could also be applied to the earlier Ironclad age Battleships, or it could be applied to the WWI Dreadnoughts (as early battleships)... it's a term that could be used, surely... but the term "Pre-Dreadnought" is a very specific term, commonly accepted in naval war colleges and in history books as an appropriate term to call a very specific design philosophy of the late 19th century and dawn of the 20th century... it's a very specific term, and it's not erroneous to call a ship a "Pre-Dreadnought".
Now if the term bugs you that much, by all means... it's a simple change in the Civ4UnitInfos.xml... just go to the Pre-Dreadnought entry and change it to read "Early Battleship" in Description (you can [and should] leave everything else as "Pre-Dreadnought"). "Pre-Dreadnought" is, however, a very legitimate term to call a type of warship... it's not something made-up... any naval historian worth his salt can tell you what one is... call yourself cultured now that you know what the term is!
P.S.
Do you need me to go-over the "Dreadnought" age as well? Or did you find that out in your research?