Today's word is VIR, which is a second-declension masculine noun.
Latin meaning and usage: The meaning of vir is "man" in the sense of a "manly man, a male person," as opposed to a woman. Contrast the word homo, which means a person, but not specifically a male person. Depending on context, vir often means "husband."
Latin word formation: There are many Latin words derived from this root, most notably virtus. Note also the adjective virilis, the adverb viriliter, and the abstract noun virilitas. There are various compounds also, such as decemviri and triumviri, etc.
English cognates and derivatives: In English the word "virtue" (with its many derivatives) is far less masculine in connotation than the Latin virtus! We also use the words "virile" and "virility," which are still quite masculine, and in Roman history books you will meet the word "triumvirate." For a great example of a cognate, compare the Germanic "werewolf" in English; you can read about the etymology of "werewolf" at Etymonline.com.
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:
Unus vir non omnia videt.
Vir quidem unus, nullus est.
Quis est vir qui vivat et non videat mortem?
Multa ante temptes, quam virum invenias bonum.
Virum facit virtus.
Aliud legunt pueri, aliud viri, aliud senes.
Qualia verba viri, talis et ipse vir est.
Facta iuvenum, consilia virorum, vota senum.
Bonus vir nemo est, nisi qui bonus est omnibus.
Quod puer non didicit, non discet vir.
Fuge procul a viro maiore.
Vestis virum reddit.
Vir unus haud videt omnia.
Cum sapiens, et bonus vir.
Vir bonus et sapiens quaerit super omnia pacem.
Qualis vir, talis oratio.
Qualis avis, talis cantus; qualis vir, talis oratio.
A sapiente viro sapientiam discere convenit.
Tarde, sed graviter vir sapiens irascitur.
Malum virum semper pati malum decet.