and a sidewalk a footpath.
If it's next to a road, it's called 'the pavement' (i.e.
http://cyclinginfo.co.uk/blog/wp-content/uploads/2008/08/pavement.jpg).
While a footpath is something you find in the countryside or residential areas - either across or round the edge of a field, or a paved path for walking on in a residential area with no roads nearby (i.e.
http://i.thelocalpeople.co.uk/275000/article/images/1968875/1412439.JPG or
http://www.beenthere-donethat.org.uk/images/winchester35.jpg).
This is really petty but I cringed for quite a while when I first realized how people in the UK say "schedule"- I just didn't get it. Are all 'sch' words pronounced like that? Is 'school' also pronounced like that? If not - why just some words?
Not all British people say schedule that way. I pronounce it the US way and always have (sked-yule). My mum says 'shed-yule' and it really bugs me

.
I can't think of any other 'sch' words that are pronounced differently here. School is generally the same as the US (sk-ool), except there are regional variations for the 'ool' part.
My husband's family (Swedish) refers to 'lunch' as 'dinner'- kind of makes me wonder if we (Americans) are the wrong ones.
I realize it's just because the English Swedes know is British English but really, if a good majority of the world refers to something one way why are Americans so weird? 
It really depends where you're from/how you grew up and also what time you eat.
I grew up in the south west of England and I call the 3 main meals breakfast, lunch and tea (although if I'm going out to eat in the evening, I will call it dinner - 'going out for dinner').
But then you do have others too:
- Breakfast: first thing in the morning
- Brunch/Elevenses: mid-morning
- Lunch/Dinner: midday/early afternoon
- Tea: late afternoon/early evening
- Dinner: mid-late evening
- Supper: late evening, before bed
So, you can have different combinations, all referring to basically the same 3 meals, depending on what you were taught/where you live/what your family uses:
- Breakfast, Lunch, Tea
- Breakfast, Dinner, Tea
- Breakfast, Lunch, Dinner
- Breakfast, Dinner, Supper
- Breakfast, Lunch, Supper