This is the 60th most frequent Swedish word.
ett
The Swedish word "ett" means "a" or "one" (neuter form).
Here, 'ett' is used as the indefinite article for neuter nouns to mean 'a' or 'an'.
Ett hus står på kullen.
A house stands on the hill.
'Ett' functions as an indefinite article for the neuter noun, emphasizing an unspecified or generic item.
Det är ett svårt problem.
It is a difficult problem.
In this sentence, 'ett' is used to indicate the article 'an' for the neuter noun 'äpple'.