My eleven year old argued with me today that I have two instruments: A piano and a guitar. When I pointed out I also have a bass, he said “That’s a guitar.”
My argument is yes, the bass guitar is a TYPE of guitar, but it’s not a guitar. You play it entirely differently. It serves a different function. I further made the argument that every piano is a keyboard but not every keyboard is a piano.
So, where does this bass community stand? Is the bass a guitar?
Yes.
+1
Yeah, the answer you’re looking for is “yes, it is a guitar”. It’s right in the name - bass guitar.
And baritone guitar. And acoustic guitar. Where it gets confusing is keytar.
Keytar ≠ guitar 
The bass is 100% a guitar
Isn’t it a portable, electric double bass?
Yes bass is a guitar. The only difference is guitar players are dime a dozen and we are always in demand 
I know that. I was trying to reference @Tarkisal ‘s statement (“My eleven year old argued with me today that I have two instruments: A piano and a guitar.”) and wondering “what is a keytar?” How would you classify it? A keyboard?
No offense intended. It’s just not a guitar. 
Like a G string is not a guitar.
I have a Roland AX9 it’s not easy strapping it’s quite uncomfortable. Not it’s not a guitar. Not this model but sounds like this.
It’s a (semi-) wearable keyboard thingie.
But def not a guitar.
I don’t know any synth player that actually likes playing a keytar, fwiw. They are uncomfortable and awkward in general. They look cool though 
A bass is a type of guitar, it’s a bass guitar. A specific type of guitar, so yes it is a guitar but you can’t just call it a guitar
Calling it simply a guitar is … wrong.
It’s a type of guitar yes, but it is not a “guitar” in typical nomenclature or definition “usually with 6 or 12 strings” without the “bass” qualifier.
If you played your bass last night and tell your friend today “I was playing my guitar last night” then your dopey (sorry, it’s true).
Words are funny
Rev. John Wheeler, formerly of SMB, played a keytar. One of the times I saw them his keytar was broken and he was playing a regular keyboard and bitching all night about wishing he had his keytar.
Bass is a guitar.
You have three instruments. Two of them are guitars. They are distinctly different types of guitars, but they are both guitars.
But to say you only have two instruments is like saying that I only have two pets because I have a dog, a cat, and another cat.
a sex inhibitor
Banjo. Accordion. Uilleann pipes. Bagpipes. Keytar. Vuvuzela (@faydout ). This list grows.