lastborn

noun

1. The youngest child of a family.

   “It took me back across the dim gulf of ages to some happy home in dead Imperial Kôr, where this winsome lady girt about with beauty had lived and died, and dying taken her last-born with her to the tomb.”

2. (figuratively)The youngest member of any company or organization.

adj

1. (not-comparable)Born last in a family; youngest in a the family.
2. (figuratively, not-comparable)Younger than anyone else in a group.