My preferred title is interaction designer.
Sure, I do a lot of other things on a day-to-day basis. Etc... ... But at the end of the day, I'm still most comfortable being an interaction designer.
This apparently annoys some people.
Well, not me specifically, but the fact that I work in and industry where we have settled on "designer." A very open discussion happened starting most seriously over a decade ago, and good arguments were put forth for "architect," and most importantly "engineer."
The thing is, I still hear this. Laments, or arguments, that as UX practitioners we work with evidence, so cannot be designers. I think this is coming from very much the wrong point of view, and gives short shrift to the concept of design.
I could use lots of marginally informed analogy. I know not nothing about process design, or instructional design. But more specifically, I went to school (but did not get a degree in) aerospace engineering, went to school for graphic design, even did some furniture design, and got a degree in fine art. Printmaking, to be precise.
In school, aerospace was mostly about the engineering, and this was explicitly stated sometimes, most clearly in some of the symposia; people from industry would come and talk to us, and show off video and slideshows of their work. I remember them being very clear about the distinction between design and engineering. One I recall was an overview of the design evolution of the landing gear on the F-18. The geometry was settled on by by the designer (the "lead engineers" were instead really "airplane designers") due to constraints in space (after several evolutions), validated by engineers, whose feedback required strengthening, then a testing program overseen by other engineers discovered the maximum sink rate (which validates it's okay for aircraft carriers, and goes in the manual).
I also more or less worked in aerospace. I did grant-funded research in high school, and got donated a lot of time from Boeing engineers and services from others. I was the first person to use the water tunnel at WSU, and was told that it was $5,000 an hour (in 1988 dollars!) if they were charging me for it. Anyway, when I ran into issues, I was of a very open, iterative mindset, and started talking about alternative designs. No, I was advised, this is the design, it appears to be fundamentally sound enough, so what we're doing is testing, validating and tweaking to improve it until we can't anymore.
Design is the idea that struck me one evening after a week at the engineering library working on a problem. Engineering is the sawing, glueing, bolting, measuring, statistics and revisions to make it a better design. But not a new one. (Iterations are possible, but on much longer timescales).
If there is a title that bugs me, it might be "Graphic Artist." I am pretty sure I was annoyed by this by the time I was 13. Yes, I have been an analytical nerd for my whole life.
I found this to be validated when I got to art school. See, our school was actually the School of Art & Design (and physically attached to Architecture, so much of my architectural analogy is based on working with those guys, but I will forego that today). But this was a bit of a strange mix. For political reasons, some introductory classes were in one school, some in the other. Photography considered itself an art form, but was in Design and regularly had curriculum arguments with their Design masters.
Design as it is taught in schools like this covers graphic design, package design, industrial design (now, very often also Interactive Design by whatever name), furniture design and some other related fields. Art is painting, printmaking (my degree!), jewelry making, textiles and sculpture. Performance was an offshoot when I went there but is getting a program these days. Photography is always an argument (some schools have two disparate programs). Yes, Visual Art (what I mean here) also usually aligns with a Performing Art school, but ours was physically far enough away we ignored that.
Back on target. Look at the list again. Design fields are aligned to outcomes. Art fields to media. Because art is for the artist, and fundamentally expresses their opinion, feelings, etc. Design serves an end purpose more than it occupies itself with the medium. Graphic Designers (not artists) can use lots of media, and often many at once, to solve their problem.
From these experiences, and from my decades in interactive design, I use these sorts of definitions.
Think about the last time a major engineering project went up in your town. The city, or state or Corps of Engineers shows off drawings for a new bridge. Everyone complains about it, and maybe there's another round of work where they change the ramps and decide to blight fewer disadvantaged neighborhoods. Then you hear nothing for like a year, and when you need see the drawings, it's 20 feet taller and has twice as many cable stays. Because that year was engineering analysis, and iterative sessions with the designers to modify the solution so it doesn't fall down.
Oh, sure, engineering analysis also led to the constraints which led to the design. Because it's not art. It's constrained by the needs of the environment and use, which are arrived at with engineering analysis and rigor. But when ideas need to be thrown on a wall that's design.
I'll say it again. It's not art. And again. Design is not art. This is, I feel, why so many shy away from giving validity to the title, or the field of design at all. There's a feeling that designers are playing, "just drawing," or just expressing their opinion.
When we sit around a whiteboard, there can be all sorts of other processes at play, but as long as we're coming up with a solution to the problem, and usually someone else's problem. we are designing. Then we evaluate it, just applying expert/heuristic knowledge, performing various task and cognitive analyses, or even sticking it in a lab. That's engineering. I prefer to work with people better at that than me, as part of a team, but don't always get to. I am comfortable calling those who are better at that evaluative side "Usability Engineers." A few organizations do, and more should.
But in the end, I am a designer, and I stand by that.