We found one dictionary that defines the word back'us boy:

Miscellaneous (1 matching dictionary)

1. BACK'US BOY, BACK'US BOY, BACK'US BOY: Terminology and Descriptions of Geneaological Words

▸ Words similar to back'us boy ▸ Usage examples for back'us boy ▸ Idioms related to back'us boy ▸ Wikipedia articles (New!) ▸ Words that often appear near back'us boy ▸ Rhymes of back'us boy ▸ Invented words related to back'us boy