one child
Refers to a single child, often in contexts like family planning or counting children.
They plan to have one child.
Describes a person who has no siblings; the sole child of their parents.
She is an only child, so she has no siblings.
one of several children; son and heir
Used when referring to one child among several, especially the eldest son who is the heir. Often appears in historical or formal contexts.
He is one of three sons and is in the position to inherit the family.
one stone
Go (game) term: a single stone. Compare with 一目 (いちもく) for 'one eye' or 'one move'.
See also: 一目
Place one stone on the Go board.
passing down secrets from father to only one child; transmission of an art or craft to a single heir
Compound of 一 (one) and 子 (child). The Go sense is a specialized extension of the 'one' meaning applied to game pieces.