Metric teaspoon and tablespoon missing

[bsidhom]

These are defined as 5 mL and 15 mL, respectively, and are used in the UK and elsewhere where metric is used. See https://en.wikipedia.org/wiki/Tablespoon and https://en.wikipedia.org/wiki/Teaspoon#Metric_teaspoon.

The situation is even more confusing than at first glance because there's also an Australian teaspoon and tablespoon.

This is an extension of #375.

[Goju-Ryu]

@sharkdp I would like to add this, but before I do I would like to know how to resolve the naming conflicts that will arise between US and the SI units.

I'm thinking either adding an SI prefix to the new units, an Imperial/US prefix to the old units or both. Any preference or other ideas?

[sharkdp]

I think it's neat to have one of them without a prefix. Because if I would use this unit, I probably wouldn't care about accuracy. I'd only be interested in a rough estimate. So let's maybe try to find out which one is more common and then add a prefix to the other?

[Goju-Ryu]

Sure, I will look into some stats on their usage. When I have something concrete I will share my findings here before implementing it.

[Goju-Ryu]

I have not been able to find any really strong data on this matter but this article and the infographic and related article below both suggest that the metric spoons are more commonly used internationally. It is however not as easy as that as they can vary by region. Australia has their own metric definition of the spoons for example.

[sharkdp]

Ok, let's just use metric as a default, and add prefixes to other units that we want to add, e.g. UK_{tea,table}spoon and potentially US_{tea,table}spoon