What Is The Origin Of The Word "Cup"?
An Old English word, from Latin cuppa. As early as 1640 cup could mean ‘a sports trophy in the form of a cup’, originally for horse-racing. To be in your cups is to be drunk. In the past you could also use the phrase to mean ‘during a drinking bout’. It is unclear which meaning is intended in this passage in the biblical Apocrypha on the strength of wine: ‘And when they are in their cups, they forget their love both to friends and brethren, and a little after draw out swords.
From Oxford Dictionary of Word Origins ?2010.