That is, in Spanish is scissors always plural like it is in English? I’m having trouble getting a clear answer out of Spanish/English dictionaries.
Chile here.
Both, but from experience i would say plural is more common, i use both in different situations. As a safe bet, stick with always plural
It’s mostly “Las tijeras”, just like in Englsih. You could use “La tijera” when you are using it as the subject - as a cartoon character or such-.
There’s a “La Tijera Boulevard” in Los Angeles. Also a quick Googling turns up a few barber shops called “La Tijera”. So it’s definitely in usage that way. I think I’d agree with posters saying “las tijeras” is more common though. Never noticed/thought about that before; it’s a bit weird.
This doesn’t answer the OP in any way, but les ciseaux is plural in French, too.
Another one for “both, but the plural is much more common”; the singular isn’t so rare that it would trigger funny looks, but I need to think hard to come up with occasions when I might use it, and those cases take the plural just fine. Spain here.
ETA: a barbershop is one of the few places where it’s used in singular in a way I can’t remember hearing in plural, to distinguish corte a tijera from corte a navaja (cut using scissors vs. using a barber’s folding knife)