Its not semantics and by any definition that is completely wrong.
NFP's (association or even companies with a ltd Guarantee structure for NFP purposes) can have a Board.
The safer definition is that a Board of Management controls the overall affairs of an organisation having been elected by its stakeholders to do so. A committee generally has a specific or set purpose, often limited in role. A committee is often called an advisory committee, or a standing committee or a sub-committee for exactly that purpose. That is not perfect but much safer than saying a board only applies to a business - that is just incorrect.
On topic, an organisation the size of Knox, with their budget, with contracts and agreements in place, and with executive and non-executive staff, would most certainly be expected to have a Board, and perhaps a series of sub-committees. But the main body, given its authority, is, and should be, a Board. That despite Knox being a NFP.