al·ter ego /'ȯl-tər-'ē-gō/ n [Latin, literally, second I]: second self; esp: a person or entity vicariously liable for another (as an agent)
had the officer been the alter ego of the corporation — J. J. White and R. S. Summers compare instrumentality
◇ The concept of a legal alter ego is used primarily to hold the controlling parties of a corporation personally liable instead of limiting liability to the corporate entity.
Merriam-Webster’s Dictionary of Law. Merriam-Webster. 1996.