This is the 437th most frequent Czech word.
hodinu
"Hour" (accusative singular form of "hodina").
The word 'hodinu' here represents a time duration, specifically 'an hour' in the accusative case to indicate the extent of waiting.
Čekal jsem na tebe hodinu.
I waited for you for an hour.
In this context, 'hodinu' refers to a 'class' or 'lesson period,' indicating a session dedicated to mathematics.
Máme hodinu matematiky.
We have a math class.
The word 'hodinu' here indicates the duration of walking, used in the accusative case to show the approximate time span.