Fermat is a lunar impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 located to the west of the Rupes Altai

Rupes Altai

Rupes Altai is an escarpment in the lunar surface that is located in the southeastern quadrant of the Moon's near side. It is named for the Altai Mountains in Asia. The selenographic coordinates of this feature are , and it has a length of about 427 km....

 escarpment

Escarpment

An escarpment is a steep slope or long cliff that occurs from erosion or faulting and separates two relatively level areas of differing elevations.-Description and variants:...

. To the west-southwest is the larger crater Sacrobosco

Sacrobosco (crater)

Sacrobosco is an irregular lunar impact crater that is located in the rugged southern highlands to the west of the Rupes Altai escarpment. It is a readily identified feature due to the three circular craters that lie on its floor. The rim of Sacrobosco is heavily worn and eroded, especially in the...

, and to the southwest is the irregular Pons

Pons (crater)

Pons is an lunar crater that is located to the west of the prominent Rupes Altai scarp. It lies to the southeast of the crater Sacrobosco, and southwest of Polybius. To the northwest along the same flank of the formation is the crater Fermat....

. It is 39 kilometers in diameter and two kilometers deep.

The rim of Fermat is worn and somewhat irregular, but still possesses an outer rampart. The north rim is indented by a double crater formation that includes Fermat A. The floor is relatively flat and does not have a central rise. The crater is from the Pre-Imbrian

Lunar geologic timescale

The lunar geological timescale divides the history of Earth's Moon into five generally recognized periods: the Copernican, Eratosthenian, Imbrian , Nectarian, and Pre-Nectarian...

 period, 4.55 to 3.85 billion years ago.

It is named for 17th century French

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 mathematician Pierre de Fermat

Pierre de Fermat

Pierre de Fermat was a French lawyer at the Parlement of Toulouse, France, and an amateur mathematician who is given credit for early developments that led to infinitesimal calculus, including his adequality...

.

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Fermat.

Fermat	Coordinates	Diameter
A	21.8°S 19.6°E	17 km
B	23.0°S 21.1°E	11 km
C	21.0°S 18.5°E	14 km
D	20.1°S 18.0°E	13 km
E	19.9°S 19.9°E	7 km
F	22.1°S 20.2°E	5 km
G	19.4°S 20.0°E	7 km
H	23.1°S 20.7°E	5 km
P	23.6°S 19.3°E	37 km