Donald Trump, turns out, did not officially change Black History Month to National African American History Month ... it's been that way for decades.

Trump's official presidential proclamation uses the words, "African American History Month" -- but President Obama did the same. In fact, since President Carter ... almost all Commanders-in-Chief have used the same language in proclamations.

There are some variations. President Reagan's proclamation in '86 referred to it as "National Black (Afro-American) History Month."

Most presidents have colloquially called it Black History Month. For example, last year Prez Obama referred to "Black History Month," despite his proclamation of "National African American History Month."

Likewise, Prez Trump referred to "Black History Month" on Wednesday.