What is the SE.Raspberry Pi accepted plural form of Pi. I have seen various offerings, some plausible, some grammatically correct but just look wrong, some which are just downright wrong... Some examples include:

  • Pi's
  • Pis
  • Pi
  • Pies

This is be no means an exhaustive list, and there are probably some other variants. Taking each in turn:

  • Pi's - this is grammatically a possessive;
  • Pis - whilst grammatically correct, the spelling is somewhat unfortunate;
  • Pi - treating the noun as a countable noun, with an irregular plural, where the plural is the same as the singular, like sheep;
  • Pies - Whilst amusing, it is obviously not correct (although I wish it was).

I personally like the Pi option. It sounds more technical, and slightly old Germanic...

It first came to my notice whilst editing the ppumkin's answer to the question, Powering Pi with a 5V regulated power supply, but I also see other people are confused, see Maehler's answer to Seems a bit premature?

Anyone how any thoughts on the matter..? Whilst it is not the end of the Earth, a little consistency would be nice.

  • Raspberry Pis sounds like what you get when you eat too many raspberry pies! Sep 24, 2015 at 6:53

2 Answers 2


You may need to also account for Pi(s) as well to indicate one or more. I would say that Pis is the right choice with the addition of Pi(s). Note that there is no way to enforce this, but editing the question/answer is the way to battle the problem. Having said that the problem is not limited to Pi, but also includes RasPi (and all of its myriad forms). This was one of the earliest questions on meta and I still see several different forms.

  • Agreed. RPi is another common abbreviation which, to be fair, seems reasonable. I shall look up this meta question, that you mention. Sep 19, 2015 at 14:07
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    @Greenonline incase you did not find the question I referenced meta.raspberrypi.stackexchange.com/questions/54/… I linked to the dupe only so you could see both. Note that this was way back in 2012 Sep 23, 2015 at 23:41

I understand the answer is not Pies but I like pie and I very much like the idea of Raspberry Pie. Prior to finding this discussion, I was quite pleased with myself yesterday when I used the plural pies in a question.


If it puts a smile on people's faces it must be OK.

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