After-born child

What does After-born child mean in American Law?

The definition of After-born child in the law of the United States, as defined by the lexicographer Arthur Leff in his legal dictionary is:

A child born after some happening of legal significance, e.g., the making of a will or execution of a deed, with respect to which the child’s appearance might have significance, e.g., to give him a share of the testator’s estate even though only the earlier born children were mentioned in the will. The most common use of “after-born child” is as a synonym for posthumous child.