Jacta est alea (L.). The die is cast.
jeu de mots (Fr.). A play on words.
jeu d'esprit (Fr.). A display of wit; a witticism.
jure divino (L.). By divine law.
juste milieu (Fr.). The golden mean.
Labor omnia vincit (L.). Labor conquers everything.
laissez faire (Fr.). Let alone; suffer to have its own way.
lapsus calami, — linguae, — memoriae (L.) A slip of the pen, tongue, memory.
lares et penates (L.). Household gods.
laudator temporis acti (L.). One who praises the past.