(~s)
1.
A ~ is a person who holds a junior officer’s rank in the army, navy, marines, or air force, or in the American police force.
Lieutenant Campbell ordered the man at the wheel to steer for the gunboat.
N-COUNT; N-TITLE
•
Lieutenant is also a combining form.
...Lieutenant Colonel Gale Carter.
COMB in N-TITLE
2.
If you refer to someone as a person’s ~, you mean they are that person’s assistant, especially their main assistant, in an organization or activity.
He was my right-hand man, my ~ on the field, a cool, calculated footballer.
= second-in-command
N-COUNT: usu poss N