denn meaning and definition in german

The normal conjunction after a comparative is als; denn is generally archaic. Only in two cases is it still found in contemporary German:
before als meaning “as, like”, in order to avoid reduplication: Er war nie glücklicher denn als kleiner Junge. — “He was never happier than as a little boy.” This usage is formal.
before je ‎(“ever before”): Er ist glücklicher denn je. — “He is happier than ever before.” This usage is normal or only slightly formal. The combination als je is not common, but one can say als je zuvor.