The terms ‘boot’ and ‘leg’ have been joined ever since working boots that reached above the ankle, probably since the 1620’s.
The term found it’s way into public jargon, as evidenced by its appearance in newspaper articles around the late 19th century. As it was still relatively new, it was ‘tried out’ in different contexts:
Related to the above, the term “bootleg soup” survived to this day and stands for a concoction based on leftovers (sometimes of questionable origin?). That certainly gives us an idea what that coffee must have tasted like…
Ten years later and the term has now firmly acquired a negative meaning, probably due to stories from the Old West about weapons, such as a knife, hidden in the upper part of a boot. I doubt it came from bottles of ‘moonshine’ actually being transported in this manner, as has often been suggested.
In 1889, a definition linking the term to illicit trade can be found:
The first case of linking the term to describe records/music that I have found, comes from a work of fiction: RENO FEVER by Dorothy Walworth Carman, published in 1932
10 years later, “the American Federation of Musicians, at the instigation of union president James Petrillo, started a strike against the major American recording companies because of disagreements over royalty payments. Beginning at midnight, July 31, no union musician could record for any record company.” [wikipedia]
Needless to say, someone saw a business opportunity and the term “bootleg” became linked with being a strike breaker.
Finally, in the 1950’s, ‘bootleg records’ started to refer to ‘pirate/unauthorized records’:
[Record Changer magazine, December 1951 issue]
RECORD ‘PIRACY’ CHARGED IN SUIT; Columbia and Louis Armstrong Allege Paradox Bootlegged ‘Jolly Roger’ Series RECORD ‘PIRACY’ CHARGED IN SUIT
January 31, 1952 – BUSINESS FINANCIAL
Reinventing itself – the meaning in 2014: