/bäks kä-ˌments/
n. Comments (explanatory notes attached to program instructions) that occupy several lines by themselves; so called because in assembler and C code they are often surrounded by a box in a style something like this:
/********************************************
*
* This is a boxed comment in C
*
********************************************/
Common variants of this style omit the asterisks in column 2 or add a matching row of asterisks closing the right side of the box. The sparest variant omits all but the comment delimiters themselves; the 'box' is implied.
Oppose winged comments.