Answer:

wheel

Answer	Crossword Clue
WHEEL	Word with prayer or paddle
WHEEL	A unicycle has one
WHEEL	People often caution against reinventing it

WHEEL	Bigwig
WHEEL	Roulette centerpiece
WHEEL	Revolver
WHEEL	Cart part
WHEEL	Revolutionary idea
WHEEL	Roller
WHEEL	Prehistoric invention
WHEEL	Potter's aid

WHEEL	Big-time operator