Today's word is CAMPUS, which is a masculine second-declension noun.
Latin meaning and usage: The basic meaning of the Latin campus is a flat place, such as a "plain" or a "field." The Campus Martius was a grassy field along the Tiber river in Rome where the comitia centuriata met. The word campus could also refer to a place of action, such as a field of battle.
Latin word formation: You can see the Latin root in the place name Campania. There are also compounds like campidoctor, also spelled campi doctor, which is the term for the drill-master who trained the soldiers in the Campus Martius.
English cognates and derivatives: Of course, we use the word "campus" in English! We also get "camp" and "campaign" from Latin campus. The English "scamper" also comes from this same root, via the Old French eschamper, from the Late Latin excampare, meaning to decamp, to leave the field. From the Late Latin word campionem we get English "champion." The name of "Camembert" cheese is from a village in Normandy once called Campus Maimberti.
Here are some examples of today's word in Latin sayings and proverbs; for more examples, see the page at the Scala Sapientiae, which also contains notes on some of the proverbs cited below:
Campus habet oculos, silva aures.
Quot campo flores, tot sunt in amore dolores.
Redeunt iam gramina campis, arboribusque comae.
Quot campus mures, tot alis, Mars improbe, fures.
Quot campo lepores, tot sunt in amore dolores.
Gramina quot campis, tot sunt in amore pericula.
Campus habet lumen, et habet nemus auris acumen.
Lumina campus habet; nemus aures fertur habere.
Magnus est in re publica campus, multis apertus cursus ad laudem.