Ikigai is a word coming from the Japanese philosophy.
Is the balance between the person, the passion (purpose) and the world.
I think that if we want to understand Ikigai's meaning, we need to ask to ourselves;
How someone can live (earn money) doing something that he likes and he is good at it (passion) and helping the world (society) ?
When you reach that stade "Ikigai" you feel in harmony, useful and in balance with life.
Like being in peace with yourself.