FIrst of all, thanks everyone for chipping in, great insights here.
It seems to me that the majority of people here have defined "seniority" with professionalism and a large repository of social skills acquired over the years.
I guess independent from that issue, the reason why I originally asked the question is when it comes to job postings. When companies advertise positions marked as senior, do they then actually mean it in the above definition?
Call me naive and unexperienced, but I'm somewhat surprised by the heavy emphasis on experience over knowledge. Is someone with more domain-knowledge but less experience more junior than someone with little to zero domain-knowledge but more experience?
When they advertise for a senior position it mostly means they want to have someone able to get things done on their own without creating problems down the road. Experience is generally a better indicator of this than domain knowledge[1]. There's very little reason not to apply for a job you think you can do regardless of the requirements. Just don't be surprised if you're filtered by HR for not having the correct buzzwords.
The best way to actually get a job is to go out and meet people. Meetups, user groups, conferences are all good. Talking to other developers directly generally gives you a more accurate picture of what it's like to work somewhere and what's actually required. As a bonus if they like you and pass on your resume you avoid getting HR filtered.
[1] Software design and maintenance are language/domain portable and are difficult to teach without direct/repeated exposure to examples, which comes over time. Unless the domain is about specialized knowledge (e.g. security) it's generally faster to teach someone the quirks of your business than it is to teach them how to design software and deal with them making mistakes.
> When companies advertise positions marked as senior, do they then actually mean it in the above definition?
It entirely depends on the company. Ones that talk about X years with tool Y are probably using a time-based definition that they hope will translate into "this person has to have enough experience to come onboard and not break everything...right?" (In my experience, this is rarely effective.)
> Is someone with more domain-knowledge but less experience more junior than someone with little to zero domain-knowledge but more experience?
I generally will trust the latter more for one big reason: they (usually) have a better grasp of their known unknowns. Every project is a backyard full of rakes to step on and while someone with more domain knowledge with regards to, say, the tech stack will definitely have valuable contributions, I personally trust more experienced folks to ask better questions and to be able to leverage the folks with domain knowledge in the formulation of a plan of action.
(This obviously is flexible. A "senior" who can't do this and a "junior" who can may very quickly swap positions in my estimation and in how I do things.)
It seems to me that the majority of people here have defined "seniority" with professionalism and a large repository of social skills acquired over the years.
I guess independent from that issue, the reason why I originally asked the question is when it comes to job postings. When companies advertise positions marked as senior, do they then actually mean it in the above definition?
Call me naive and unexperienced, but I'm somewhat surprised by the heavy emphasis on experience over knowledge. Is someone with more domain-knowledge but less experience more junior than someone with little to zero domain-knowledge but more experience?