posthumously is incorrectly written, and should be written as "posthumously" being its meaning:
Adverb so that means a posthumous way, subsequent to the death, after death, following the death of someone, which obviously it is said when someone or something appears or is born or sees the light when it has died its author or creator. It is thus of posthumous son or posthumous literary works or last wills. Postumus - a - um in latin means last, postremo, last.
