כֹּל מַפְרֶסֶת פַּרְסָה וְשֹׁסַעַת שֶׁסַע פְּרָסֹת מַעֲלַת גֵּרָה בַּבְּהֵמָה אֹתָהּ תֹּאכֵלוּ
Whatever has a cloven hoof that is completely split and chews its cud among the animals, that you may eat.
The Hebrew word for cud is gera. Rashi speculates that it might be related to the word meaning to draw as in “mayim hanigarim” – “drawn water” – in II Samuel 14:14. The reason for this would be because animals that chew their cud draw it back into their mouths.