The Posuk Says (Gen. 25,2223):
שְׁנֵי [גיים] גוֹיִם בְּבִטְנֵךְ וּשְׁנֵי לְאֻמִּים מִמֵּעַיִךְ יִפָּרֵדוּ
Translated as: Two nations are in your womb, and two kingdoms will separate from your innards
What is the diffrence between a גוֹיִם and a לְאֻמִּים