The average person tends to get the terms computer cabinet and computer rack confused. The problem is that they seem to think that they are talking about two completely different items. In certain instances, you could be talking about two different products. However if you are working in the IT field and assembling a new server system, the two terms are for the most part interchangeable, with one major exception.
Computer Cabinets Tend to Be at Least Partially Enclosed
The one difference that you are going to notice between a computer cabinet and a computer rack is that the term cabinet often denotes a rack has both side panels as well as doors on the front that may or may not be lockable. Based on the servers you are using and your need for security, these might make a better choice, however you need to choose a cabinet that is going to provide plenty of cooling air to your servers.