We can all cut and paste, acronyms form words from initials, not necessarily relating to the initials, so what word is NATO or NASA used in relation to speech/written word outside of their common usage.SSS are initials the others are words.
A word is a speech sound or a combination of sounds, or its representation in writing, that symbolizes and communicates a meaning and may consist of a single morpheme or a combination of morphemes. The branch of linguistics that studies word structures is called morphology. You appear to be confusing parts of speech.
You appear to be mixing up your cut and paste articles.