Most architects, I believe, define the terms furnish (or supply), install, and provide, and sometimes those definitions appear in an owner's general conditions. When defined, they are part of the contract documents, and requirements using them are enforceable based on those definitions. In practice, perhaps because the definitions are nearly ubiquitous, I have had few problems with interpretation by contractors, or with enforcement.
Oddly, it's architects who seem to have the most trouble understanding and using these definitions, even though the definitions originate in the architect's own office.
In casual conversation, it's common to use furnish and provide interchangeably. This should be no surprise, as the first definition of furnish is either provide or supply in every definition I found, and definitions for provide usually are make available, supply, or cause to be present, all of which also mean furnish.
When used in casual conversation outside the office, there usually is no problem as no further precision is needed, and we aren't concerned about installation. However, when used in casual conversation in the architect's office, or in conversation between architect and owner, there is at least a potential problem.
If a specifier, or an architect who cares about such things, is involved in the conversation, it's likely that the precise definition will become part of the discussion, and the related contract documents will use the correct definitions. But without the involvement of such a person, it's quite possible that the contract documents will use the wrong, or conflicting, definitions.
A similar problem exists with references meant to indicate either who is furnishing or who is providing something, for example, by owner or by contractor. I have seen countless references of this sort, and each time asked what the intent was. The responses have been inconsistent, sometimes meaning furnished by and other times meaning provided by.
To further complicate the issue, I have seen increasing use of the term vendor. In the context of the construction contract, there typically are two or three of these defined entities: The owner, the architect, and the constructor (contractor, CM, or design-builder). Everything must be furnished, or installed, or furnished and installed, by either the owner or the constructor. In my experience, a "vendor" is most often a company that works directly for the owner, either furnishing materials for installation by the constructor, or furnishing and installing materials for the owner. In either case, an additional term is not required, because the vendor works for one of the defined entities. A vendor that works for the owner is, in the context of the contract, indistinguishable from the owner; and a vendor that works for the contractor is a subcontractor.
In casual conversation, incorrect use of defined terms may be an inconvenience, but when defined terms are used imprecisely in conversation with a client, whether in formal or informal communication, incorrect interpretation is almost inevitable.
To eliminate these problems, consider avoiding the term provide, and using instead, the slightly longer, but unmistakable furnish and install. Some would argue this is not necessary, and I agree. However, in balance, the advantage of clarity and the elimination of the need to continually discuss the speaker's intent can outweigh the simplicity and elegance of using provide.
How often have these definitions led to problems for you?