The kanji for 鉄拳 seems to suggest that the word means "iron fist". However, various dictionaries suggests that the meaning is simply "fist".
For example, Edict shows that the meaning for 鉄拳 is "fist", and the meaning for 鉄拳制裁 is "punishment by striking with fist".
Does 鉄拳 mean "fist" or "iron fist"?
How does it's meaning and usage compare with 拳 (こぶし)?