This is the 874th most frequent Czech word.
velkém
"Velkém" means "big" or "large" in the locative singular form in English.
The word 'velkém' is in the locative case, indicating location 'in the big house'.
Bydlíme ve velkém domě.
We live in a big house.
The word 'velkém' specifies the location of the action, situated 'on the big square', using the locative case.
Na velkém náměstí bylo dnes mnoho lidí.
There were many people at the big square today.
The word 'velkém' here is also in the locative case, describing the subject of the discussion 'about the big problem'.