To debark is to disembark, which is to get off of an airplane or ship or other mode of transportation. Both can also be the act of removing someone or something from the same vessels. Both have noun forms of debarkation and disembarkation, which refer to the location the person debarked at.
Additionally, one can debark a tree, or remove the bark from a tree. One would then be a debarker.
My wife heard a cracker mis-usage the other day. Someone told her, “I
used to be a member, but then they dismembered me.” Oh dear!
Originally, I suspect, the word embark meant ‘to go aboard a ship’, and debark meant ‘to leave a ship’– a barque. Disembark appears to mean ‘to undo the going aboard of a ship’, but is popular because it doesn’t seem to refer to the denuding of trees…