This is the 1st most frequent Finnish word.
ja
"Ja" means "and" in English.
Here, 'ja' is a conjunction that connects two adjectives describing the house, making it coordinate.
Talo on iso ja punainen.
The house is big and red.
Here, 'ja' connects two nouns in a list.
Otan omenan ja appelsiinin.
I will take an apple and an orange.
In this sentence, 'ja' connects two subjects to form a compound subject.