“Sator Arepo Tenet Opera Rotas” is a Latin phrase known as the Sator Square. It's a word square containing a five-word Latin palindrome
The individual words can be translated as:
SATOR: sower, planter; founder, progenitor (usually divine); originator
AREPO: unknown, likely a proper name, possibly of the “sower”
TENET: keeps, holds; comprehends; possesses; masters; preserves
OPERA: work, care; aid; service, effort/trouble
ROTAS: wheels