It has been proposed that CTO, representing Configure to Order, be merged with Build to Order. While related, they are separate concepts.  The term Build to Order can be used for anything that can be built, and is similar to JIT, Just In Time manufacturing. CTO, however, is only applicable to the set of products where configuration is actually possible. Thus, CTO does or could require BTO, but is a small subset of BTO. With that said, from an end users perspective, they don't or should not actually care about the "build" part of the process, they just want what they want. Thus, if something had 100 different configurations, whether or not a particular configuration is actually "built" or simply shipped from stock is irrelevant to the end user.