“Two of my least favourite words in the English language are ‘business casual’ as it means different things to different people,” said Joyce Newman, president of the Newman Group, which offers high-level speaker, media and image consulting to global executives. “The definition varies widely between cities, countries, cultures – even industries – and it’s a real dilemma for travellers because you never get a second chance to make a good first impression.”

Firstly, business casual dress varies between men and women. While men are often safe wearing khakis and a button down shirt, the permutations for women are endless. "Business casual for women can best be categorized by what it's not than by what it is. For example: no jeans, no shorts, no low necklines, no miniskirts, no stiletto heels,” said globetrotting Claudia Kozma-Kaplan, who heads up marketing for the Leading Hotels of the World.

In some regions, the term business casual simply does not translate. Frankfurt-based financial industry executive Johannes Jacobi said. “Most Germans feel more comfortable in the familiar suit and tie – invitations to business casual events in the US or elsewhere are usually met with angst and a lot of questions.”

Also, appropriate business casual attire in one country or region is not always acceptable elsewhere. An Indian executive might feel comfortable wearing a traditional kurta (a loose fitting shirt worn by men and women that extends to just above the knees; worn with pants) to an event in Hyderabad, but would probably feel awkward wearing one in New York. Similarly, a Puerto Rican executive who might wear a guayabera shirt to a business casual event in San Juan should probably leave it at home when travelling on business to London.

On the other hand, should a visitor wear a kurta or guayabera when visiting India or San Juan? Bermuda shorts in Bermuda? Maybe… or maybe not. According to Newman, calling ahead for advice is the best way to avoid the potential embarrassment of over- or under-dressing at an unfamiliar business casual function.

“Ask someone who has been to a similar event in that country before,” counselled Newman. “Use your travel agent, your friends or social media networks for advice about what to wear. Eventually, with ‘six degrees of separation’, you will find someone in-the-know.”

Beyond the safe global standard of jackets or blazers, khaki or gray slacks, and leather shoes, below is a primer to how business casual varies around the world.

“Business casual is essentially the same for both men and women in Australia,” said Sydney-based management consultant Peter Braithwaite. "If it's an event, men should wear a collared shirt, pants and jacket, with leather shoes. You may find jeans, but that is pushing it a bit. For women, a skirt, dress or pants are okay. Heels aren’t necessary, but never sandals -- for men or women.”

In Latin-influenced islands such as Cuba, the Dominican Republic and Puerto Rico, local men frequently wear informal-looking guayaberas to business casual or formal events —even weddings. On the other hand, women tend to “dress up” in cities such as San Juan where “casual Fridays” usually mean high heels, flashy jewellery and bright colours. But proper attire could differ on the next island over. “When I first went to the Caribbean, I was expecting business casual to be the norm, but was surprised at how formally locals dressed in places like Trinidad, Barbados, Jamaica and Haiti due to the European influence on their cultures,” said international development consultant Linda Carlson.

Europeans use business casual as an opportunity to show off their character and fashion sense. “Europeans know how to express themselves and be comfortable at the same time, while most Americans tend to think it’s mostly about just being comfortable,” said Patrick T Cooper, a US-based fashion consultant. Cooper recently returned from an extended trip to London where he was impressed by men “in two-button, peaked lapel, ticket pocket, double-breasted blazers with British spread collar shirts (no tie) and light wool slacks — all tailored, of course, to fit perfectly.” He said that women may have a tougher time with the business casual look in Europe, and thus may want to stick to their regular business attire, even when attending business casual events. “There’s no real letting your hair down when it comes to business attire for women. For women who normally wear suits at work, I would take it down just one notch for business casual, to a tailored pants suit or a poplin top and a pencil skirt. And never any flashy or dangly jewellery,” he advised.

“In India, business casual means jacket, trousers, collared shirt, no tie and oxford shoes for gentlemen. For ladies, it is jacket, trousers, inner t-shirt and low-heeled pumps,” advised Ashrafi Matcheswala, who recently moved from India to the US where she is the general manager at the Taj Campton Place Hotel in San Francisco.

Carlson, who spent three years in India, added, “The many Indians who have spent time working in technology jobs in California returned focusing on the more casual side of business casual, but they’ve ‘Indianized’ it by incorporating the local kurta into the look.”

“Japanese business attire has definitely become more casual over the last three to four years,” said Jun Mizutani, head of marketing at Tokyo-based RCM Japan.

However, casual varies slightly from industry to industry. For example, many executives have shed the traditional suit, or coat and tie during the summer, except for those in the financial or securities industries which remain mostly formal.

Last summer, the Japanese government launched the “Cool Biz” campaign to encourage office workers to shed their formal work clothing and adopt business casual outfits to endure the summer heat, which lead to a greater acceptance of casual styles at work or at off-site events. Similarly, the “Warm Biz” campaign encourages office workers to consider adding more knits and layers as thermostats are turned down to use less heat for winter.

United States
The definition of business casual varies from coast to coast in the US, the country that likely coined the term. Along the more formal East Coast, business casual typically infers a “preppy” look: a dark blazer, jacket or sweater for men and women, a collared shirt (tie optional), a skirt (for women) or pressed slacks (no jeans) and leather shoes. The look gets more casual the farther you travel west. For example, in Denver or Seattle, business casual takes on a more “outdoorsy” look and includes jeans, boots, vests and jackets that might look familiar on a hiking trail than in a business meeting. When you finally reach California, business casual can include just about anything, and varies a lot by industry. For example, a business casual event in the banking or finance industries would likely lean toward the more conservative East Coast version. But in high tech or entertainment, business casual could include jeans and a black t-shirt (think Steve Jobs) or even floral Hawaiian shirts. All the more reason to heed Newman’s advice to call ahead and determine precisely what you should pack before you leave home.

Chris McGinnis is the business travel columnist for BBC Travel