the.com/defenseman

means A hockey player positioned primarily to break up opposing rushes and protect his own goal, typically operating in a pair with another defenseman.

from A straightforward compound of 'defense' plus 'man' — hockey borrowed its early organizational vocabulary from established team sports, and as positions formalized in the late 1800s and early 1900s, the player stationed back to guard the goal simply got named for his job. No hidden story here — the word means exactly what it says, which is rarer in etymology than you'd think.