In defining what concept is, the human intellect took and takes, many approaches most of them driven, I would dare say, by some kind of ulterior motives, or hidden agenda. Individuals applying biased views of looking at things, struggled to convince others, experts and the public, about the validity of their arguments drawn into embittered battles making it a personal quest but not a quest for truth.
The end result is, the meaning of concept remains largely obscure and its usefulness in the human endeavour, in either personal or collective level, to make sense of the world ambiguous. An obstacle that hinders natural growth.
Among the definitions present up to date, one that bears significance and assists human mind in search for answers in a personal and collective level is the approach put forward by William James
"In order to understand the meaning of the concept and to discuss its importance, a concept may be tested by asking, "What sensible difference to anybody will its truth make?" There is only one criterion of a concept's meaning and only one test of its truth. That criterion or test is its consequences for human behavior."
Looking at human behaviour in its broad sense including the efforts for elucidating the rules and mechanisms that underpin reality, making sense of what is going on around us, we acquire meaning by using concepts, concepts taken from the viewpoint of what sensible difference its use will make while the person is in the process of probing reality, what would the consequences be in altering his understanding about the process probed.
As meaning lies in people, meaning conveyed by concepts, the concepts used in the process to understand the underlying reasons of a phenomenon probed, we achieve meaning and understand the phenomenon as long as we have embraced the full extent of the concept's implications as these are expressed by the concept's properties, extensions, and other particular qualities contained herein.
Each time a concept is enriched by the addition of extra qualities, whatever that may be, a discovery process itself, it will result in a re-arrangement of our understanding, our very own conceptual arsenal increase, adding extra dimensions and improving our sense of the world.