No
OK. That is an oversimplification. If you're writing about history, a wreck, or one of 10 museum ships, then it could be a battleship. But if you're talking about an active military vessel, then it is not a battleship.
This is a battleship. Important identification features include lots of guns and being tied up in port.
The term you are looking for is "warship", which is the correct generic for "ship that fights". "Battleship" is a technical term for a large, armored, gun-armed ship, a type built from about 1860 to 1945, and that hasn't been in service since 1992. I have written about them extensively. Yes, they sound like they should mean exactly the same thing, but they very much do not, and referring to anything in active service as a "battleship" comes off rather like someone calling all newspaper staff "editors".
This is a typical modern warship. (A destroyer, to be precise.) She has only one gun and is at sea. If either of these are true, the ship is not a battleship.
Now, if you want to be even more accurate and refer to a relevant ship by a more specific type, the best place to look is its Wikipedia article. I am very much not joking here. Warship Wiki is generally excellent, and nobody is going to mock you for using the designation it does. Unfortunately, modern ship designation is pretty arbitrary, but if want a very high-level overview, I have written A Spotter's Guide to Modern Warships, which links to other posts on the various types, as well as a high-level discussion of how we got into the mess we are in.
P.S. You are also probably making the same mistake with respect to the term "tank", although tanks are actually something still in use today. I'll let Bret Devereaux explain that one.
Comments
Ah, that brings back memories of a favorite headline:
https://www.theinertia.com/news/mexican-navy-sinks-old-battleship-to-create-an-artificial-reef-off-coast-of-rosarito/
Possibly worth mentioning for context: Traditionally, navies reserve the term "battle" for fights involving large fleets of ships on both sides; anything with just one or a few ships on a side is an "action" or "engagement". Kind of like the difference between "battle" and "skirmish" in a land war. Since any war is going to have a lot more small-unit actions than full-scale battles, most warships are going to be optimized for the small-unit actions and given a supporting role in the real battles. So "battleship" means that, no, we really built this one to win major battles.
Since WWII, the ships we build to win major battles are called "aircraft carriers", or possibly "ballistic missile submarines".
Ballistic missile submarines are designed for shore bombardment, not defeating enemy ships.
Most of the enemy's ships will probably be in port for the first hour of the war.
....Could be worse: I have the last reissue of the old Monogram USS Chicago (CG-11), which is proudly emblazoned with the words BATTLESHIP CHICAGO on the box cover.
I suppose the Chicago was at least a reasonably large armoured surface combatant. Pre-refit it had a sizeable gun armament, and afterwards it was one of the most heavily armed surface combatants in the world. I wouldn't give them a pass on this as it would just confuse things, but it is much closer than a patrol vessel with a 40mm.
Why would that be? Assuming there's a substantial increase in geopolitical tension prior to the commencement of armed conflict, a fair percentage of both sides' fleets will be at sea when the war begins.