It can mean many things

Apathy

Lack of understanding

Cowardice

Meditation

Contemplation

But it can also mean

Things falling into place

God behind the scenes

The slow heal of the drip drip drip of antibiotics

Quiet understated move

Wordless embrace

Grace note in the song

Silenced bullet hitting the target

Unspoken prayers of the heart

Sometime the silence speaks 

Even screams

But you must listen well

With all of your being

All that you are 

Otherwise you will miss it all

The hidden

The true grace

The power of the infinite

The voice of God