USA/Canada flights operate on the piece concept, i.e. you can check two bags.
On all other flights the allowance is determined by weight alone.

You will be allowed two bags. If flying business these can each weigh up to 70 lbs, in economy they can weigh 50 lbs each. If you are in economy and have one bag of 70 lbs they might charge you for the 20 lbs overweight.