De mortuis nil nisi bonum

The recent death of a neighbour, who incidentally was a good egg, brought the phrase de mortuis nil nisi bonum to mind.

Aurorae

There are two auroras in astronomy: the aurora borealis or northern lights and the aurora australis or southern lights.  The Latin edition of wikipedia gives a much shorter explanation.

aurora, - ae  (f)  dawn, morning; goddess of dawn; the East
auster, -ri  (m)  south wind, south
australis  adj  southern
Boreas, - aw  (m)  north wind, north
occidens, occidentis  (m)  west
oriens,  orrientis  (m)  east

Pro tanto quid retribuamus

Pro tanto quid retribuamus is the motto of the city of Belfast and also of HMS Belfast.  It comes from the Book of Psalms in the Latin Vulgate edition of the Bible - psalm 116 verse 12.  It means: "For so much, what shall we repay."

Benedictus benedicat

Benedictus, Benedicat per Jesum Christum Dominum Nostrum is a Latin grace for saying before a meal.  Apparently, it means: "May he who is Blessed bless [this food] through Jesus Christ Our Lord." 
 
Benedicto Benedicatur, per Jesum Christum Dominum Nostrum is the corresponding closing grace.

Silent leges enim inter arma

Silent leges enim inter arma was Cicero's famous observation in Pro Milone.  It means: "Of course, the laws are silent in war."  These days the laws are certainly not silent about war.

Lupus in fabula

Lupus in fabula, which literally means "the wolf in the story", is the Latin equivalent of "talk of the Devil."

Nullius in verba

Nullius in verba is the motto of the Royal Society.  Literally it means "nothing in words".  The essence of the motto is: "Take nobody's word for it."

nullus, nullius (dat -i)  adj  no, none; not, not at all
verbum, -i  (nt)  word

Domus Aurea

The Domus Aurea was a large landscaped palace built for the emperor Nero at the heart of Rome after the great fire in 64AD.

domus, -us  (part 2nd & part 4th declension)  (f) house, home, family
aureus, -a, -um  adj  golden

Ignis aurum probat, miseria fortes viros

"Ignis aurum probat, miseria fortes viros" means "Fire tests gold, misfortune (tests) strong men."  It is clearly an excellent proverb.

ignis, ignis  (m)  fire
aurum, -i  (nt)  gold
miseria, -ae (f)  misery
fortis  adj  strong; brave
vir, viri  (m)  man

probo, -are, -avi, -atum  to approve; to appraise; to prove

Incidentally, the scientific abbreviation for the element gold is Au from aurum.