<P> Master is used sometimes, especially up to circa late - 19th century, especially in the UK to describe the male head of a large estate or household who employs domestic workers . </P> <P> The heir to a Scottish lordship, barony or viscountcy is given the style or dignity Master of followed by his father's title . For instance, the heir of Lord Elphinstone is known as the Master of Elphinstone . </P> <P> Nancy Tuckerman of the Amy Vanderbilt Complete Book of Etiquette writes that in the USA, unlike the UK, a boy can be addressed as master only until age 12, then is addressed only by his name with no title until he turns 18, when he takes the title of Mr., although it is not improper to use Mr. if he is slightly younger . In former times enslaved African - American addressed their oppressors as master as a term reflective of their forced and unpaid labor . Some of the enslaved Africans would often pronounce it in a colloquial dialect as "massa". Robert Hickey, deputy director of the Protocol School of Washington, states that "use of Master (as) an honorific when addressing boys is considered old fashioned outside of conservative circles ." </P>

When does a boy go from master to mister