number one son

Definition

(Expression) A term of affection and/or respect used by parents to refer to either the first born male child, or any male child. "One" thus can refer simultaneously to birth order and preference. Often used without an article (a, the, my, etc.).
Origin: In the Charlie Chan movies of the 1920s-1950s, Charlie, a Chinese-American, refers to his son as "number one son." In some scenes, this is a term of pride: "Number One Son has studied well." In others, it is tinged with irony, nevertheless reflecting parental love in a not-too-bright moment: Upon his son stating the obvious, Chan comments: "Number One Son is very observant."