(idiomatic) It is not possible to repeat past experiences, as time changes all things.

(cliché, idiomatic) (used imitatively) A cliché used to exaggerate an accomplishment or milestone.

The son of one's spouse, but not one's own child.

The daughter of one's stepparent who is not the daughter of either of one's parents. / The stepdaughter of one's parent which is not one's half-sister.

plural of stepsister

plural of stepson

plural of stepsibling

The child of one's stepparent from another relationship

(informal, endearing) A stepsister.

(mathematics) The size of a step.