Section Eight vs dismission

Section Eight and dismission both are nouns.

Word	Noun	Adjective	Verb	Adverb
Section Eight	Yes	No	No	No
dismission	Yes	No	No	No

As nouns, dismission is a hypernym of Section Eight; that is, dismission is a word with a broader meaning than Section Eight:

Section Eight: a discharge from the US Army based on unfitness or character traits deemed undesirable
dismission: the termination of someone's employment (leaving them free to depart)

Other hypernyms of Section Eight include discharge, dismissal, firing, liberation, release, sack, sacking.

Section Eight (noun)	dismission (noun)
a discharge from the US Army based on unfitness or character traits deemed undesirable	the termination of someone's employment (leaving them free to depart)
a soldier who received a Section Eight discharge as unfit for military service	official notice that you have been fired from your job