梯子はしごの段だんMeanings1nounrung of a ladderRefers to the horizontal crosspiece of a ladder. The word is straightforward and literal.梯子はしごの段だんが一ひとつ壊こわれている。One rung of the ladder is broken.梯子はしごの段だんに足あしをかけて登のぼる。I climb by placing my feet on the rungs of the ladder.