In preparing an article for The Catholic Herald, the UK’s best Catholic weekly, I ran across something fun I wrote for the now concluded WDTPRS series’ look at the Third Eucharistic Prayer.
Mundus, a, um is an adjective for “clean, cleanly, nice, neat, elegant” and “morally pure, upright, free from sin” as in the famous phrases from the Vulgate “cor mundum crea in me Deus… create in me a pure heart O God” (Ps 50 (51):12) and, “beati mundo corde … blessed are the pure of heart” (Matthew 5:8). In the Extraordinary Form of the Roman Rite, before the the Gospel the priest says the prayer called the Munda cor meum:
“Cleanse my heart and my lips, O Almighty God, Who cleansed the lips of the Prophet Isaiah with a burning coal. In Your gracious mercy deign so to purify me that I may worthily proclaim Your holy Gospel.”
As an aside, mundus, -i refers in the first place to “a woman’s dress or ornamentation” such as cosmetics. It is also “the universe, the world, esp. the heavens and the heavenly bodies” and thus “the earth, the inhabitants of the earth, mankind”. This is the equivalent of the Greek kosmos, whence is derived English cosmos and cosmetics.