What is the meaning of Hatt?

Obsolete form of hat.

indefinite accusative singular of hattur

past participle of hebben

hat

Alternative form of hat

hat (head covering)

past participle of ha

hat (head covering)

stressed third-person neuter singular, nominative and accusative: she, her; (rarely: it)

a hat

the top bread slice of a semla

a member of Hattpartiet [the Hats party]

Source: wiktionary.org