Deductions & credits

What is the definition of "not otherwise reimbursed"?

For example, assuming I am the one contributing to the HSA, and my wife has insurance through her employer. 

In a hypothetical situation, she encounters a medical bill of $600, of which $500 is reimbursed by her insurance and $100 is her responsibility. In this case, no one is reimbursing her for the $100, so can I use my HSA card to pay for it?