M21 or M-21 may refer to:
The M16 was a 4.5-inch (110 mm) spin-stabilized unguided rocket developed by the United States Army during the Second World War. Entering service in April 1945 to replace the earlier fin-stabilised M8 rocket, it was used late in the war and also during the Korean War before being removed from service.
Developed during the latter stages of the Second World War, the M16 was the first 4.5-inch (110 mm) unguided, spin-stabilized rocket to be standardized for production by the United States Army.31 inches (790 mm) in length, it could hit targets as far as 5,200 yd (4,800 m) from its launcher. The M16 was launched from T66 "Honeycomb" 24-tube launchers, and could also be fired from 60-tube "Hornet's Nest" launchers. The United States Marine Corps developed launching systems for the M16 rocket as well, capable of being fitted to standard 3/4 and 2.5-ton trucks. A version of the M16 rocket for single launchers, the M20, was developed as a derivative; practice rounds designated M17 and M21 were also manufactured.
The M9 and is a local bus routes that operates along the Avenue C Line (also known as the Houston Street Line), in Manhattan, New York City, United States. The route runs mostly along Essex Street and Avenue C from Battery Park City to Kips Bay. Originally a streetcar line, it the Avenue C Line is now part of the M9 route, as well as the M21, which operates on the Houston Street Line. The M9 is operated by the New York City Transit Authority, and based out of the Michael J. Quill Depot.
The Avenue C Railroad (changed to the Houston, West Street and Pavonia Ferry Railroad in the early 1880s) was chartered June 3, 1874, and opened the Avenue C Line on October 18, 1869, connecting the Pavonia Ferry at the foot of Chambers Street with the Green Point Ferry at the foot of East 10th Street. Its route ran along West Street, a one-way pair of Charlton Street, Prince Street, and Stanton Street (eastbound) and Houston Street, 1st Avenue, and 3rd Street (westbound), Pitt Street/Avenue C, and 10th Street. By 1879, the line had been extended north on Avenue C from 10th Street, west on 17th Street (eastbound) and 18th Street (westbound), north over the Central Park, North and East River Railroad (First Avenue and East Belt Line) on Avenue A, 23rd Street, and 1st Avenue, west on 35th Street (westbound) and 36th Street (eastbound), north on Lexington Avenue, and west on 42nd Street to Grand Central Terminal. The Third Avenue Railroad also used the trackage on 42nd Street by 1884.
I thought you were a friend of mine but I was wrong
You tried to fit into the arms where I belong
You moved right in behind my back
Everyone knows friends don't do that
I thought you were somebody I could trust
You always said you were happy for us
How could you go and break my heart?
When you knew all along he was mine from the start
He is everything to me
And you know we're meant to be
He's my baby
Don't mess with my love
Take everything I own
Ooh just leave that boy alone
He's my baby
Don't mess with my
Mess with my love
Don't mess with my love
You came right over and looked in my eyes
You said the stories were rumors and lies
And I wish I could believe in you
But I'm sorry to say he told me the truth
He is everything to me
And you know we're meant to be
He's my baby
Don't mess with my love
Take everything I own
Ooh just leave that boy alone
He's my baby
Don't mess with my
Mess with my love
Don't mess with my love
Friends don't do what you do
There's no excuse
I'm so confused
I thought you cared about me
But now I see
All you care about is you
He is everything to me
And you know we're meant to be
He's my baby
Don't mess with my love
Take everything I own
Ooh just leave that boy alone
He's my baby
Don't mess with my
Mess with my love