The palm-forward "V" sign, formed by raising and spreading the first two fingers, has three different meanings in American culture.
掌心向外, 豎起食指和中指, 并向兩邊展開, 這樣就構成了一個V形手勢。V形手勢在美國文化中有三個不同的含義。

The most popular meaning of the "V" sign was invented in 1941 by a Belgian, Victor De Lavalaye. Wanting a symbol for resistance to the Nazi occupation, he came up with the single letter "V", which stood not only for his own first name, but also for English victory, Flemish virijheid, and French victoire. The symbolism of the sign spread very quickly, and Winston Churchill used it constantly in public appearance. Thus throughout the 1940s and 1950s, the gesture meant simply "victory".
V形手勢最為普遍的一個意思是在1941年由比利時人維克托· 德· 拉維雷創造發明的。他用V形手勢來表示他對納粹占領比利時的反抗。這個V 不僅代表他的姓氏, 而且還象征英語中的victory ( 勝利) 、佛蘭芒語virijheid( 勝利) 和法語victoire ( 勝利) 這三個單詞。這一手勢的象征意義迅速地傳播開來, 溫斯頓· 邱吉爾在公眾場合就曾多次使用。因此, 在20世紀40年代和50 年代, 這個手勢只是表示“ 勝利”的意思。

The second meaning came in the 1960s. Because of its military implication, American antiwar protestors used the sign sarcastically against the arms, so that it became known as the "peace sign". In the 1970s, the "V" sign, which had lost its military implication, was a common greeting among freedom lovers, acid heads, political radicals, and ultimately, young people in general. So by about the middle of the 1970s, it ceased to give clue to the user's philosophy.
V 形手勢的第二個意思出現在20世紀60年代。由于這個手勢含有軍事方面的意思,美國反戰者就諷刺性地用這個手勢來反對戰爭, 于是, 這個手勢開始被稱為“ 和平的標志”。20世紀70年代, V 形手勢失去了軍事方面的含義, 成為熱愛自由的人、嗜用迷幻藥的人、政治激進主義者們見面問候時常用的手勢, 并最終在廣大年輕人當中流傳開來。也就是說, 大約到20世紀70年代中期, 這個手勢就不再表示使用者的人生觀了。

The third meaning is the oldest and least common. American children jokingly put "V", which resembles "horns", behind friends' heads in group snapshot. They are unknowingly reproducing something that southern Europeans would find highly offensive. This mischief, called "horns of the Devil", is a variant of the European "horns" gesture, which is obscene. Here the "V" sign means "Your wife has been cheating on you" or, when placed behind another's head, "His wife has been cheating on him.
V 形手勢的第三個意思最為古老, 也少為人用。在集體照相的時候, 美國孩子常開玩笑地在朋友的腦袋后面擺出手勢V, 樣子就像動物的角一樣。 他們無意中做出了一個被南歐人視為相當無禮的動作。這種被稱作“ 魔鬼之角”的惡作劇是歐洲“ 角形”手勢的變體,這種手勢被認為具有淫穢的意味。在南歐, 手勢V 表示“ 你的老婆對你不忠”。在別人腦袋后面做出這種手勢, 如同在說“ 他的老婆對他不忠”。

In the United States, the gesture is typically given with the palm facing the viewer. The British use both this version and an older, palm-backward version; the latter is obscene in American culture, and corresponds to the American "finger". Churchill got some surprised stares in 1941 when, evidently unaware of the vulgar usage, he gave the palm-backward "V" to British troops. In England today you could have to be a social hermit not to understand the distinction. Astonishingly, however, Margaret Thatcher repeated Churchill's error after her victory in the 1979 election.
在美國, 人們通常將掌心向外, 面向對方做出這個手勢。而英國人有時將掌心向外, 有時則掌心向內。掌心向內的V 形手勢在美國文化里被看成是下流動作, 與美國人豎起中指一樣具有淫穢的含義。1941年, 邱吉爾掌心朝內, 向英國軍隊擺出了V 形手勢。一些士兵吃驚地盯著他看, 顯然他對這個手勢的下流含義還全然不知。如今, 在英國, 如果你還不知道掌心向內和向外的差別的話, 你一定是個不問世事的隱士。然而, 令人驚訝的是, 瑪格麗特· 撒切爾在贏得1979年的選舉之后, 又重蹈邱吉爾的覆轍, 做了一個掌心向內的V 形手勢。

（來源：滬江英語，編輯 Helen）