"Toilet", "lavatory" or "loo" for polite society

My friend is trying so hard to fit into polite society, and is raising her child to say loo rather than toilet. I know it should be lavatory (and I would not say lav) but we are in the 21st century now. What would be deemed appropriate?

Solution 1:

In the UK, people would be happy if you say loo.

An alternative to loo is lavatory, which is something you might hear in higher class circles.

Toilet is fine, but will make some, more old fashioned, people wince.

If you say "bathroom" (as in MrHen's answer) in the UK, people will probably understand you, but if you are out and about (rather than in someone's home) then they might be a little confused.

We don't tend to use "restroom" in the UK, but, again, most people will understand you.

Other euphemisms for toilet in the UK, that are used in polite society, include

Male toilets

• Gents (as in gentlemen's)
• Mens
• Little boys' room

Female toilets

• Ladies
• Little girls' room

Toilets

• WC (water closet)

and somethings I've only heard from my granddad's generation:

• Latrine(s)
• Ablutions

Solution 2:

The answer you are looking for entirely depends on where the child is being raised. In the Midwestern US, for instance, the most polite word is restroom:

Where is your restroom?

If you are in someone's house you can also use bathroom. Most of the US considers these two appropriate.