As with many fashion concepts and styles, there is no single rule of etiquette for the business casual dress code. Although the formal definition of business casual offers a general rule of thumb for men, actual business casual etiquette varies by region, industry, and even company.
For example, in California, Jeans might be acceptable business casual attire, but on the East Coast anything less than dark wool pants might be considered too casual. In additional to the region, industry and company pages linked above, below are some general rules of thumb, guidelines and concrete business casual examples about what is considered appropriate business casual attire.
Dark Wool Dress Pants
Long-Sleeved Button Down Shirts
Black Dress Shoes
Matching Sport Coats
Polo Shirts
Clean-Cut Jeans
Sandals
Shorts
Suits
T-shirts
Tennis Shoes
Ties
Tuxedos