Aye
Form one (Ei, Ai, Aye - by itself):

Ei (eventually changed to Ai in middle English and Aye in modern English)

Used to confirm which group has a majority in a decision. It should never be the reply of an individual unless that person is representing a group. An example would be when a group votes yes or no. When the vote is counted if more votes are yes then the person representing the group would respond "Ei". In reference to the modern British use of the word, when the Vikings used to raid the coastlines they would take people prisoner to become conscripts, the crew would vote to kill the person or make them part of the crew. If they voted to make them part of the crew the reply to the captain would be a single "Ei"

It is important to note the word does not mean "Yes". 

It simply means the majoirty or a group confirms or agrees.

This term when used correctly is directly related to Aye-Aye or Ei Ei. Also, see Y-Aye-Man
"Captain": Does the crew accept this man, as a brother in life?

"Crew representive": Aye (Ei)

