Who was the first black american to be honored on a postage stamp?

Explanation:

Booker T. Washington Postage Stamp. On April 7, 1940, the Post Office Department (POD) issued a stamp honoring African-American educator Booker T. Washington (1856-1915) as part of its Famous Americans Series. The nation's first stamp to honor an African-American, it holds a unique place in American history.

Booker T. Washington

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.