This is the 914th most frequent Czech word.
americká
"Americká" means "American" (feminine singular form) in Czech.
Here, 'americká' is an adjective describing the noun 'vlajka', indicating that the flag is from or related to America.
Toto je americká vlajka.
This is an American flag.
In this context, 'americkou' is the accusative feminine form of the adjective 'americká' agreeing with the noun 'uniformu', showing its direct object role.
Měla na sobě americkou uniformu.
She wore an American uniform.
Here, 'americké' is the plural nominative form of the adjective 'americká', describing movies as being associated with America.