Joy is not a Latin word, so there is no definition for it. If you mean what is a Latin word for joy, then there are several: gaudium, laetitia, exultatio
The English word 'joy' has several meanings: 1: something or someone that provides a source of happiness; 2: the emotion of great happiness; 3: feel happiness or joy; 4: make glad or happy
Catervae is the Latin equivalent of 'hordes'. It's a feminine gender noun. Its first, original use in Latin is in reference to a 'troop of barbarian soldiers or mercenaries'.