北美的宴會或舞會，請貼上一般都會注明著裝要求（Dress Code），分以下幾種情況：
一，White Tie或者說是Ultra－formal ：
這是最最正式的場合，什么授勛儀式、宮廷晚宴之類的，我們平常百姓大概一輩子也碰不上一次。男士要穿燕尾服（tailcoat），配套的是白色馬甲，白色襯衫，白色領結。褲子兩側(cè)有兩道筆直的豎條。褲子不用皮帶用吊帶。
女士要穿大裙擺的長晚禮服。
二，Black Tie或者說是Formal ：
這是最常見的正規(guī)著裝要求，男士要穿晚禮服（Tuxedo），前襟領子是黑緞面的，配白襯衫，黑領結，黑腰帶，黑襪子，黑鞋。褲子兩側(cè)夾縫有和領子同面料的黑緞夾條。如果一年趕上那么一次半次的，可以去租全套設備回來用，省心省力。
女士穿晚禮服（Evening gown），低胸露肩的那種，相配的小包和鞋子。項鏈、耳環(huán)等首飾的真假無所謂，但是要閃亮，戴手鐲而不是手表。
妝要濃一些，俺看到許多知識分子同胞在宴會場所化淡妝或者根本不化妝，那臉在燈光下慘淡的沒法看，而且不化妝是十分失禮的一件事，比穿了不合適服裝還要讓人不舒服。
中國女士可用面料好的剪裁得體的旗袍或改良旗袍代替晚禮服，穿旗袍時，頭發(fā)挽起來配上頭飾效果會比清湯掛面好很多。
三，Black Tie Optional 或者是Creative Black Tie，
男士可以穿Tuxedo或正式的深色圓擺西裝，可以不打領結換成打領帶，襯衫最好是白色的，
女士可以是晚禮服、不拖地的四分之三長禮服或者是考究的晚宴兩件套（dressy separates），配備參考Formal。
四，Semi-formal
男士：深色西服
女士：短禮服、考究的套裝
五，Cocktail
雞尾酒會一般在下午4點到7點舉行，屬于半正式著裝，（Semi-formal）男士穿深色西裝，女士穿短裙或套裝，長度和白天服裝相同，但用料要講究，天鵝絨、絲綢緞子之類的，顏色要比白天的服裝明亮，華貴，配上閃亮的首飾，可搭配圍巾。要穿高跟鞋。
妝比白天要濃。
六，Dressy Casual
男士：比較講究一點的便裝，像西裝上衣配休閑褲，襯衣休閑西褲等。
女士：連衣裙，漂亮上衣配褲子，毛衣配裙子等可以自由發(fā)揮。
七，Business Casual
比Dressy Casual 再隨便一些，但是不能穿牛仔褲。
八，Casual 或Informal
這種說法意味著可以隨便穿，但是短褲、涼鞋還是要避免，當然你也不要西裝革履的。
有時越隨便的穿著，越能看出人的品味，不能掉以輕心。女士穿一件質(zhì)地普通的連衣裙肯定比穿牛仔褲雅致?；瓓y。
總的原則，你比別人穿的相對正式一點比穿的隨便要好。
Black tie, known in the United Kingdom (and also in the north-eastern United States, and Canada) as a dinner jacket and in the United States generally as a tuxedo, is a dress code for formal evening events that are not formal enough to require white tie.
Black tie is today worn at a wide variety of functions, and the corresponding female attire can range from a short cocktail dress to a long gown, depending on fashion, local custom and the hour at which the function takes place.
History
The American name tuxedo is taken from Tuxedo Park, New York, a private club of country houses founded by Pierre Lorillard, the tobacco heir. (The town of Tuxedo and Tuxedo Park themselves were named by the Lenni-Lenape Indians, who called the largest lake in the area tucseto, meaning either place of the bear or clear flowing water.)
Traditionally, the first Autumn Ball, held at the Tuxedo Club in October 1886, marked the official first American appearance of the English dinner jacket, which was favored by the fast sporting crowd round the Prince of Wales, who liked to wear a "Cowes" jacket, somewhat like a formal mess jacket, first at dinner aboard his yacht during the regattas held at Cowes, and then later at other evening entertainments, though never in London. The original single- breasted model was simply a tailcoat without a tail, worn with a white piqu?vest as would be worn with a tailcoat, then later with a black vest ensuite with the jacket and trousers.
At the 1886 Tuxedo Park Autumn Ball, Pierre Lorillard's young son Griswold Lorillard and his friends startled guests, all in white tie and tailcoats, by wearing the new English dinner jackets, with scarlet evening vests. The tailless coats were similar in cut to hunting pinks worn in daytime at foxhunting meets. When after 1889, gentlemen in "tuxedos" were even admitted to the Dress Circle at the new Metropolitan Opera, the success of the new fashion was made.
The American upper classes now generally prefer the terms "black tie" or "dinner jacket" to "tuxedo", which is considered slightly vulgar.
Early evening clothes were uniformly black. The Duke of Windsor, when Prince of Wales, introduced midnight blue as an appropriate color, and even made the double-breasted dinner jacket acceptable.
The waist sash called cummerbund (or cumberbund) was borrowed after World War I, from military dress in British India.
What it is
Other Styles
Coloured bow ties, waistcoats and cummerbunds are widespread at parties, but not appropriate at more formal occasions. On the other hand, wearing a white bow tie with a dinner jacket is considered a grave solecism (though the first dinner jackets were worn with white ties). Coloured or patterned dinner jackets are sometimes seen but are not appropriate at formal occasions. In the United States, the wearing of a collarless shirt without a bow tie, closed with a stud or banded, has become fashionable, but would again not be seen e.g. a state dinner.
Cufflinks and shirts studs can be black, white, silver, or gold, and a white handkerchief and flower may be worn. In recent years it has become acceptable to wear state decorations with black tie at state events. In such cases only one neck ribbon and one breast star are worn, with miniature medals.
In the United Kingdom, it is felt in some circles that wing collars are properly the preserve of white tie, and that a shirt with a soft turn-down collar should be worn with black tie. However, in its earliest form black tie was always worn with a stiff white shirt and stiff wing collar. White waistcoats, such as those worn with white tie, remain an acceptable alternative to black.
Black tie, having originated as an informal dress code for e.g. dining at home, has no single accepted form of headgear. Generally a soft black felt hat such as a homburg may be worn together with an overcoat.
Corresponding forms of dress
In the armed forces, officers normally wear mess uniforms which correspond to evening dress or black tie. These vary according to the regiment or corps, but usually involve a short Eton style jacket that comes to the waist. Some forms include white shirts and black bow ties, while others have high mandarin collars that fasten around the neck. They are usually brightly coloured and ornamented with gold lace and buttons, corresponding to the regiment or corps.
In the Royal Navy there is a distinction between "mess dress", which is worn at white tie events, and "mess undress", which is worn at black tie events. Both are worn with a black bow tie, however mess dress is worn with a white waistcoat instead of the usual blue.
Scottish dress is often worn at black tie events, especially at Scottish reels and ceilidhs. While there is a more formal version which may be worn when the dress code is white tie, the black tie version is much more common, even at white tie events.
The traditional black tie version of Highland dress consists of:
The Lowland version of black tie is a variation on normal black tie, with trews worn with a normal dinner jacket or Prince Charlie jacket. Trews are also often worn during the summer and in a warm clime.
In the United Kingdom black tie is only properly worn in the evening, i.e. after 6 p.m.. However, in some other places such as the United States, it has become common to wear black tie at four o'clock weddings and evening weddings. At Harvard in the 1960s, young men in dinner jackets seen during the late afternoon hastening towards an event would be hailed by ironic cries of "Check, please!"
Black tie is worn at many private and public dinners, dances, and parties, and it would be impossible to draw up a comprehensive list. At the most formal end it has taken over from white tie at many occasions where the latter would formerly have been worn, e.g. by orchestra conductors. In the United States, it commonly appears at proms and is worn by men at weddings even during the day. (see tuxedo rental).
