"Пара" stands for "пара академічних годин" (a pair of academic hours, and not a pair of classes). One academic hour is 45 minutes, so one "пара" is 90 minutes. 90 minutes is a standard duration of one class in many universities and colleges. Therefore, one class = one "пара."
A lot of things in Ukraine will not make sense to an American, but it makes things interesting, I think. One academic hour is a typical class duration in primary schools. There it is called "урок." Counting the duration of classes in academic hours is also typical for Germany. They are called "Semesterwochenstunden" there. Having different duration of classes for primary and for higher schools becomes common in the US too. It is called block scheduling..
This is the FIRST time I've heard that 'пара' refered to a 'two-houred class that is worth 45 minutes each hour!!(And here I thought that they were talking about shoes!) THAT's comfusing!
We just call a 'class' а 'кляса' and a 'lesson' an 'урок' or a 'лекція'. (This is in Canada of course.)
It's great we're describing these differences to eachother. It's a great way of learning from eachother.
Дякую вам всім за цікаве спілкування!
Пара is the most common way to call a university class. Not in elementary or middle school though, there it's just урок or заняття; high school - depends on the high school :) Mine wanted to sound serious and academic, so they used пара to make students feel like adults :D