The story
Initialism of One Big Happy Weasley Family, since the ship results in two of the main characters in the series, Harry Potter and Hermione Granger, ending up with two of the seven Weasley children.
Etymology from Wiktionary, CC BY-SA 4.0.
OBHWF
Today it means: The double ship of Hermione Granger/Ron Weasley and Harry Potter/Ginny Weasley from the Harry Potter series. Full definition →