"Ordinary" refers to an "ordinary expense" as defined in IRS Publication 463.  "Ordinary" is one of the tests that must be passed in order for an employee business expense or travel expense to be tax deductible.  IRS Publication 463 defines an ordinary expense as one that is:

...common and accepted in your field of trade, business, or profession.

This means an expense is considered ordinary if it is common and accepted in your job as a professional truck driver.  In other words, if many of other truck drivers are likely to also incur the applicable expense, it should be considered ordinary.

The following list could be considered ordinary expenses within the trucking field, yet they still may not be tax deductible until other tests are passed.

• A cell phone bill.
• A wristwatch.
• A road map.
• A GPS.
• A computer.
• Internet fees.
• Socks.
• iPod.

Again, the list of expenses above are NOT necessarily tax deductible for truckers. They are simply "ordinary". Other tests must be passed to be tax deductible.