Its Another END

I came back early from office on 23rd Oct 2018  as one of my close neighbour passed away . It was a sad demise  and I was back to square one on my all-time curious phenomenon "Death "

With energy almost drained out,  was sitting with papa in his room and suddenly papa said a word which hit me : There is no definition of life yet
And he was very true . He has written in his daily dairy as well but i was blank ...how do you define life , what makes a life and why death is always sudden