More data points:

baHjan                                launcher
 peng baHjan                     (photon) torpedo launcher
botjan                                 shield(s) [the mechanism?]
 begh botjan                       deflector shield(s)
qa'vam jan                         Genesis Device
Saqjan                                 landing gear
voDmeH jan                      drill
wab labwI' jan                  radio transmitter
wovmoHbogh jan            light

And in referring to Klingon communicators:

  janmey ngo' lulo'lu'DI' pIj jabbI'ID nISpu' woj
  Older models were susceptible to radiation.  (S19)

Voragh

From: nIqolay Q

On Mon, Apr 8, 2019 at 8:48 AM Daniel Dadap <daniel@dadap.net> wrote:

I don’t know where Klingons draw the line between what is a {jan} and what is not, but I never felt like “sophistication” was one of the criteria for that.

Another data point: paq'batlh uses wIjwI' jan "farmer's device" to mean "plow".