How I learn the word" bro" I am pretty suck with english cuz my English is pretty basic. when people said slang words, I just barely understand. One time, my American friends saw me greeting like," Hi what's up? bro?" I was like," what the hell is bro?" then he didn't say anything but gesture like unfolding his hands on top of the heads. I was like," Is that mean "boom"? . He said," yea". from now on, I use "bro" in the writing when I wanted to describe something or similes. One day, teacher asked me why do I use the informal words in the writing. I said that this is American friends told me to use it as "boom".