IPA: /ˈdʒɔɪəsnəs/
KK: /ˈdʒɔɪəsnəs/
The state of feeling very happy and full of joy.
The joyousness of the celebration was felt by everyone in the room.
Joyousness → It is formed from "joy" (from Old French *joie*, meaning happiness or delight) and "-ous" (meaning full of) and "-ness" (meaning the state of). The word "joyousness" means the state of being full of joy or happiness.
Think of 'joy' as happiness, and remember that 'joyousness' means being full of that happiness.