What does など mean? How should it be translated into English?
Some translators automatically translate it as "etc." Others have other strategies, such as "such as," "and others," "for instance," and "for example," for example. Many translate it sometimes and ignore it sometimes. This last, context-sensitive strategy is probably the best, but how are we to decide?
On rare occasions the choice is clear. A book I translated some years ago contained the following sentence:
「国民の祝日に関する法律」が施行されたのは、昭和23年（1948年）のこと。この時点での祝日は年間9日 （現在は14日）で、「建国記念日」「敬老の日」「体育の日」「みどりの日」「海の日」などはなかった。The arithmetic is easy. Here など clearly does not mean "and others," for there are no others.
More often, though, it is hard to know. Take this sentence from a paper that I translated about road tests of wheel bearing grease:
試験終了車両を含め現在までのところ、いずれの車両においても焼き付きなどのトラブルは発生していない。From the context, the など could only refer to problems with the wheel bearings (not, say, the dashboard clocks). Does the author mean that there weren't any instances of 焼き付き or other wheel bearing problems or only that there weren't any instances of 焼き付き? I'm going to guess the former, but I know from experience that the latter might be true, too.
Some kokugo dictionaries are unambiguous about the ambiguity. From the 岩波国語辞典 definition:
などI once remarked on Honyaku that I thought that など sometimes served as a kind of plural marker, but 岩波国語辞典 explicitly denies that:
<副助>《体言・用言だけでなくいろいろな表現を受けて》例として示す意を添える。同類のものが他に有っても無くてもよい。
(ア) 同類としてとらえる事物の代表例に挙げるのに使う。「その事は国会―で問題になった」「菓子や茶―を売る店」「私が事故にあう、妻が寝込む、娘が浪人する―、この１年ろくな目を見なかった」
(イ)（同類のものが無くても）具体例として持ち出すのに使う。「彼―はなかなか立派な仕事をしている」「お前のぐち―につきあっていられるか」「卒業したら学校に―近寄らない」... (6th edition, 2000)
(ア)(イ)とも複数化する表現ではない。I'm not completely convinced, though. The fact that the dictionary denies the plural meaning suggests that someone has asserted it.
What started me thinking again about など was this passage in 辞書をつくる(現代の日本語) by 見坊豪紀 (玉川大学出版部, 1976). Regarding a dictionary definition he wrote for the word 球趣, the author remarked:
これは「野球・ボーリング・ゴルフの……」と解説するのもはばかられるので、「野球などの」として処理した。 （「など」ということばは、辞書編集上の魔法のことばである！）A magic word for lexicographers, a devilish word for translators.
(July 8, 2005)