Who is God (Deva) ?

God in Sanskrit is 'Deva'
Deva is derived from the root 'divu'
Divu means : 'divu kreeDaa, vijigeesha, vyavahaara, dyuti, stuti,swapna, moda,mada, kaanti, gatishu'

A crude translation would be : Divu is to mean -- game,above-all, business, light, praise, dream, joy, pride, glow,end-of-all

• Deva is one, for whom the whole world is a game; from creation of this world till its destruction, its all a game for Him. He does not have to perspire to create this world. Everything is His leela. So He is known as deva
• Deva is one, who is above everything else, who is taller than the tallest, higher than the highest, bigger than the biggest and greater than the greatest. So He is known as deva
• Deva is one, who takes care of all the day-to-day business of this world, who looks into all the activities of each and every being, without whom, nothing moves --tena vina truNamapi na chalati. Thus He is deva
• Deva is one who is the source of all light, the light through which everything lights up-sun,moon,stars-the light through which everyone sees, the light which sees everyone. Hence, He is deva
• Deva is one, whose praise is sung by all the words spoken by every being. Every sound produced in the universe is nothing but His praise. So, He is deva
• Deva is one, whose dream -is this world; the one who makes us dream, the one who is responsible for dream, sleep and awakening of all beings. Hence, He is deva.
  

While each and every meaning is more than sufficient to talk about His greatness forever, the remaining meanings can be similarly deduced.
(From, lectures by BG)