This is the 826th most frequent Swedish word.
röda
"Röda" means "red" (plural or definite form) in English.
Here 'röda' is an adjective describing the definite noun 'huset' (the house). Swedish requires the definite form of adjectives when describing definite nouns.
Röda huset står vid sjön.
The red house stands by the lake.
In this case, 'röda' is the plural form of the adjective 'röd', agreeing with the plural noun 'blommorna' (the flowers).
Blommorna är röda.
The flowers are red.
Here 'röda' is used again as the plural form of the adjective 'röd', describing the plural noun 'äpplen' (apples). Adjectives in Swedish change form to agree with the number and definiteness of the nouns they modify.