Today's word is POSSUM, which is an irregular verb; you can see its conjugation here.
Latin meaning and usage: The word has the same basic meaning as the English "be able to" or "can." It takes a complementary infinitive, and it can also take a direct object, e.g. Dii omnia possunt, "The gods can (do) all things."
Latin word formation: As you can probably guess from the -sum at the end of the verb, possum is actually a compound of the adjective potis, meaning "able" or "capable," and the verb sum. In archaic Latin writers, you can find potis sum instead of possum. If you keep in mind that possum is basically a compound form of sum, it is easier to remember the various irregular forms of the verb! The Latin adjectives possibilis and impossibilis are both formed from this verb, and as are potentia, potestas, etc.
English cognates and derivatives: In English, from these Latin words we get the words "possible" and "impossible," along with words like "potential" and potent," as well as "power." Meanwhile, the English word "posse" from the Latin phrase posse comitatus, "the power of the county."
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:
Non omnia possumus omnes.
Dii omnia possunt.
Non possunt primi esse omnes omni in tempore.
Si vis, potes.
Aliud est velle, aliud posse.
Bonus esse non potest aliis malus sibi.
Qui potest capere, capiat.
Cura omnia potest.
Plus potest plurium cura.
Nullus omnia scire potest.
Dum potes, vive.
Vivimus, non ut volumus, sed ut possumus.
Nihil non potest fortis animus.
Quis sine amico vivere possit?
Alterius ne sit, qui suus esse potest.
Cuncta potest facere deus.
Non possunt omnia simul.
Bene vixit is, qui potuit, cum voluit, mori.
Dare nemo potest quod non habet.
Satis est beatus, qui potest, cum vult, mori.