Common Phrase Meanings and Origin  |  B-Letter Idioms
Note: Finding the origins for sayings and phrases can be very difficult a lot of the time, as it's hard to find that one person or even area where an idiom started. For the most part, what's given are possibilities in how a phrase could have originated, but not necessarily how it actually did. Additionally, early recorded forms of a saying will be given, and these tend to come from old books, newspapers, poems, or plays.

However, if phrases are being printed in forms of media, like a newspaper, that's usually a sign to show it's already a well known saying, and is probably much older. Ultimately, you get an approximate on how long a phrase has been used for, and gain a little understanding on where a phrase's roots are from. - Sayings and Phrases - Meanings and Origins
Breaking down a social stiffness to make things more comfortable.

This phrase is sometimes used when the cold social awkwardness is broken between two people who are meeting for the first time.
Some may say that this phrase comes from, or at least was made popular, by steam-powered icebreaker ships that were designed in the 1800s for sailing in polar regions of the world. As the name suggests, these ships were designed to move and navigate through ice-covered waters, which can be quite challenging. Nevertheless, using the ship's strengthened hull and powerful engine, it can break the ice apart into smaller pieces, allowing the ship to pass through without too much difficulty.

However, by the looks of it, this phrase actually preceeds the creation of the icebreaker ships. This expression goes back to at least the 17th century, written in a poem by Samuel Butler in 1678. There's a line from the poem that reads:

"To give himself a first audience, After he had a while look'd wise, At last broken silence, and the ice."

Reference: Wikipedia - Icebreaker Ships
* Carl introduced me to his new friends and I felt a little uneasy at first, but the ice was quickly broken soon after meeting them.

* Paul was set to give a speech in front of a large crowd and was incredibly nervous, but he broke the ice with his audience by starting out with a funny joke.
The origin of phrase Break the Ice.
The meaning of the saying Break the Ice.

A list of phrases starting with the letter B.
Phrases and Idioms