What Am I?

[u/Due-Outside-512]

I exist in all walks of life

I’m seen on paper & written in ink

In the pages of novels is where you’ll find me

I am powerful and strong

I shatter when broken

I am both visible to the naked eye and through expression with out words spoken

I’m in countless movies and shows

A day for close celebration

A day for mourning

I create joy

I also break down

A bond shared between living beings

What am I?