Initialism vs Determined - What's the difference?

As a noun initialism

is a term formed from the initial letter or letters of several words or parts of words, but which is itself pronounced letter by letter.

decided; resolute, possessing much determination.

(determine).

(wikipedia initialism) (en noun)

A term formed from the initial letter or letters of several words or parts of words, but which is itself pronounced letter by letter.

BBC is an initialism for British Broadcasting Corporation.

* Acronyms selected for your enjoyment * English words suffixed with -ism

(en adjective)

Decided; resolute, possessing much determination.

I'm determined to get a good grade in my exam.

(head)

(determine)