Here's a list of one word albums, off the top of my head, that were released before Rihanna was even born:
1999 - Prince
Abacab - Genesis
Animals - Pink Floyd
Autoamerican - Blondie
Bad - Michael Jackson
Caribou - Elton John
Confrontation - Bob Marley
Control - Janet Jackson
Desire - Bob Dylan
Exodus - Bob Marley
Fragile - Yes
Graceland - Paul Simon
Help! - The Beatles
Hysteria - Def Leppard
Innerversions - Stevie Wonder
Legend - Bob Marley
Pearl - Janis Joplin
Presence - Led Zeppelin
Quadrophenia - The Who
Revolver - The Beatles
Rumors - Fleetwood Mac
Sleepwalker - The Kinks
Tapestry - Carole King
Thriller - Michael Jackson
Whitney - Whitney Houston
the awkward moment when only one of her album titles is one word and that there were many albums with one word titles long before she even hit the scene