IDW: volume 5 or not volume 5?

[neatoman]

If we're going by the logic that it's a book published in the USA simply under the title "Teenage Mutant Ninja Turtles" without anything like "Adventures", "Tales of" or "Universe" attached, then IDW's TMNT would actually be the sixth series with that title.

Teenage Mutant Ninja Turtles (Mirage 1984) 62 issues.
Teenage Mutant Ninja Turtles (Mirage 1993) 13 issues.
Teenage Mutant Ninja Turtles (Image 1996) 23 issues.
Teenage Mutant Ninja Turtles (Mirage 2001) 32 issues (possibly more coming but it's unlikely).
Teenage Mutant Ninja Turtles (Dreamwave 2003) 7 issues.
Teenage Mutant Ninja Turtles (IDW 2011) 100+ issues.

So technically, you could call this series "Volume 6", if you really wanted. But like others have said, it's not a continuation of anything which makes that terminology a bit unfitting (though in-universe it's impled that the IDW-verse might be a be split timeline from the Mirage world that has been further screwed up due to patching up after a bunch of reckless time travel). I don't like the "Volume" terminology myself because it gets confusing wheter you're talking about the issue numbering or the trade numbering.

If you really feel like you need an easy way to differentiate the book from any previous iteration, I might suggest you simply call it "IDW TMNT". And if IDW ends up rebooting or simply starting over with a new issue 1, then it might be best to call it "TMNT 2011".