A Brown Deposit Resembling Soil

Dictionaries have their comic twists,
Intentional or not, as in this
Definition, not for what you may
First think, but in fact for humble peat.
Rot and corpses and decay make fuel.

All waste, by definition not fuel
For whatever system wasted it,
Is fuel—the cosmos will recycle
All of this, and all your knowledge is
Only the not-yet digested bits.