the b in b-boy stands for Break, in the 70's when there was a 'break' in a song (which is when there is no vocalisation and just the rhythem) that was when the dancers would get down and do thier thing, the boys that danced on the 'break' were called b-boy same for the girls 'b-girl'

male breakdancer

most people beleive that b boy only means breakdancing but there arefive elements of a b boy
1 breakdancing
2 mcing (rapping)
3 tagging (graffiti)
4 djing
5 beatboxing
all of these elements are the makings of a b boy

1. male breakdancer(says it's originally break boy)

2. male from the bronx(says it;s originally bronx boy)

3. i b boy, you b boy, he b boys - doing breakdance moves.

B Boy, The "B" stands for Beat. A Beat boy has anything to do with a beat, this entails: Rap, Breakdancing, Mixing, and some say graffiti.

The words 'Break Boy and Break Girl' originated from the Bronx of New York. In the early 70's Dj Kool Herc would play the 'breaks' of songs. Meaning, he would only play parts of the songs where it was beat only, no lyrics. This would excite the people to dance. So in turn girls and guys who danced to these 'breaks' were called 'Break Boy and Break Girl' or 'B-Boy; B-Girl' in short.
B-boying started with the James Brown's 1969 "Get on the Good Foot". When on stage James Brown would dance around with such energy and almost acrobatic moves, many people began mimicking his moves, so they called it the "Good Foot". The 'Good Foot' was mainly dancing around that involved drops or spins on the floor. Thus, the beginning evolution of breaking.
During the 1970's martial arts were also very popular, so B-Boys (for the most part) incorporated martial art stunts to 'wow' the crowds. And today b-boying has evolved into a highly demanding dance physically and mentally. With massive b-boy dance competitions being held around the world, such as BOTY (Battle of the Year) in Germany and the FreeStyle Sessions.

It is important to know that the term b-boy cannot be used for an emcee, DJ or rapper. Only breakers can be called b-boys.

Also b-boys do not like to be called "Break-dancers", as this was a term coined by the media in the 80's, and is not a 'true' hip-hop' phrase. Break-dancers are dancers who have no style and show their powermoves to get props from people who have no idea about breaking.

Breakdancing, also known as breaking and b-boying.

butt boy

B-boying is an urban name for breakdancing. People that study breakdancing from all aspects and generally live the Hiphop culture prefer to call breakdancing B-boying, simply because they fought breakdancing became to commercial and people that could do one move would call themselves b-boys or breakers. This is perticaly annoying to people that have focused all their lives on hiphop and then some guys think their bangin or cool because they can do a simple move. This is why most b-boys refer to breakdancing as B-boying.

NOTE: Street Dancers are not b-boys. Street dancing is stupid POP like dance with a street name to make it more appealing to the YOUTHS AND URBANS. Movies like you got served are absolutely fake although it does have some elements of Breakdancing, in the real world it would be b-boying not things you see Backstreet boys do.