The Sator Square is a word square

Word square

A word square is a special type of acrostic. It consists of a set of words written out in a square grid, such that the same words can be read both horizontally and vertically. The number of words, which is equal to the number of letters in each word, is known as the "order" of the square...

 containing a Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 palindrome

Palindrome

A palindrome is a word, phrase, number, or other sequence of units that can be read the same way in either direction, with general allowances for adjustments to punctuation and word dividers....

 featuring the words SATOR AREPO TENET OPERA ROTAS written in a square

Square (geometry)

In geometry, a square is a regular quadrilateral. This means that it has four equal sides and four equal angles...

 so that they may be read top-to-bottom, bottom-to-top, left-to-right, and right-to-left. The earliest known appearance of the square was found in the ruins of Pompeii

Pompeii

The city of Pompeii is a partially buried Roman town-city near modern Naples in the Italian region of Campania, in the territory of the comune of Pompei. Along with Herculaneum, Pompeii was destroyed and completely buried during a long catastrophic eruption of the volcano Mount Vesuvius spanning...

 which was buried in the ash of Mt. Vesuvius in 79 AD. Its widespread appeal has been characterized as being a meme

Meme

A meme is "an idea, behaviour or style that spreads from person to person within a culture."A meme acts as a unit for carrying cultural ideas, symbols or practices, which can be transmitted from one mind to another through writing, speech, gestures, rituals or other imitable phenomena...

.

If the Sator Square is read boustrophedon

Boustrophedon

Boustrophedon , is a type of bi-directional text, mostly seen in ancient manuscripts and other inscriptions. Every other line of writing is flipped or reversed, with reversed letters. Rather than going left-to-right as in modern English, or right-to-left as in Arabic and Hebrew, alternate lines in...

, with a reverse in direction, then the words become SATOR OPERA TENET, then the sequence reversed.
: Sower, planter; founder, progenitor (usually divine); originator
: (arrepo) (I) creep/move stealthily towards, also trust, or likely an invented proper name; its similarity with , from , 'I creep towards', may be coincidental
: holds, keeps; comprehends; possesses; masters; preserves
: (a) work, care; aid, service, (an) effort/trouble
: (rota) wheel, rotate; (roto) (I) whirl around, revolve rotate; used in the Vulgate Psalms as a synonym for whirlwind and in Ezekiel as plain old wheels.

One likely translation is "The farmer Arepo has [as] works wheels [a plough]"; that is, the farmer uses his plough as his form of work.