Today's word is CORAM, which is an adverb; in addition it also serves as a preposition.
Latin meaning and usage: The basic meaning of coram is "in the presence of." It is also used as a preposition with the ablative case. It is a rather unusual preposition in that sometimes the complement of the preposition can sometimes come first: te coram, "in your presence."
Latin word formation: The word coram is probably connected to the Latin word for mouth and also face: os, gen. oris
English cognates and derivatives: As far as I know, there are no English derivatives of this Latin word.
Here are some examples of today's word in Latin sayings and proverbs; for more information, see the page at the Scala Sapientiae, which contains notes on some of the proverbs cited below:
Luceat lux vestra coram hominibus.
Cantabit pauper coram latrone viator.
Vacuus cantat coram latrone viator.
Cantabit vacuus coram latrone viator.