Secondhand smoke refers to the smoke that is exhaled by a person who is actively smoking, as well as the smoke that comes from the burning end of a cigarette, cigar, or pipe. When someone is exposed to this smoke, either by breathing it in directly or being in an environment where it lingers, it is referred to as secondhand smoke. The term "stream smoking" is not commonly used or recognized, so it's unclear what it specifically refers to.
