Today's word is VOX. As with many third-declension nouns, the nominative reflects the noun stem voc- with an added s at the end: voc+s = vox. You can see the same root in the Latin verb voco.
We have an abundance of English words that derive from this Latin root, including the word "voice" itself (from old French voiz, in turn derived from the Latin vocem). Other English words include "vocal," "vociferous," "invoke," "revoke," etc. The English word "vowel" also comes from this root, as a littera vocalis, a letter that can be voiced (unlike consonants, which cannot be pronouned on their own without a vowel sound).
The Latin word vox covers a range of meaning from any kind of call or cry or sound in general, while also referring to some kind of specific utterance, so that it can even mean a "saying" or "word" (for example, a word in a dictionary is a vox, and the meaning of the word is listed sub voce).
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, as well as additional proverbs:Vox unius, vox nullius.
Vox populi, vox Dei.
Melior est vox operis, quam vox oris.
Multum viva vox facit.
Vox audita perit, sed littera scripta manebit.
Et lacrimae pondera vocis habent.
Nescit vox missa reverti.
Flectitur iratus voce rogante deus.
Vox sanguinis clamat de terra.
Validior vox operis quam oris.
Vox operis validior est, quam oris.
Vox et praeterea nihil.
Vox est potentior ense.
Ostia cur claudis, si vocem pauperis audis?
Dissimilis cunctis vox, vultus, vita, voluntas.
Si vox est canta; si mollia brachia, salta.
Ne si bos quidem vocem edat.
Ego vox clamantis in deserto.
Vox clamantis in deserto.
Corvus voce crocitat sua.