Definition of "eldest" []

• Greatest in age or seniority. See Usage Note at elder1. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Otto is what I called my eldest son who is in the imperial navy!"
• "They are brothers; and the eldest is a baronet, has a good estate, a wife and three or four children."
• "Usually, the 2nd, 3rd and 5th sons are sprawled on our bed while watching cartoons on cable TV; the eldest is engrossed on highstreet 5 while the 4th son plays mafia wars on facebook."