Is authorisation a typo?

[myl7]

When translating I found many authorisation. authorization should be a much more common spelling. Though authorisation does exist, it feels strange and is rarely used.

[spencerwooo]

lol, I would feel offended if I were British.

[spencerwooo]

I just came back from Scotland, it's hard to change these spelling habits when everyone around you uses s instead of z.