A knife produced in a stated finite quantity, often with a serial number marked on the blade or bolster. The number tells you the run size and the piece's place in it. Whether that translates into value depends entirely on how large the run is and whether anyone wants it.
A mark such as 47 of 500 says the maker committed to producing 500 and this is the forty-seventh. Low numbers, and particularly number one, sometimes command a premium among collectors, though that is a market convention rather than a rule.
The number is only meaningful if the maker actually honors the limit, which reputable manufacturers do.
A run of 5,000 is not scarce. Neither is a limited edition that a maker repeats every year in a new color. Scarcity is about how many exist relative to how many people want one, and a large run fails that test regardless of the label.
See what makes a knife collectible.
Keep it sealed and boxed if value matters. An opened, handled limited edition is worth meaningfully less than a sealed one, and a sharpened one has left the category.
Some of the pieces in our Licensed & Movie category are produced this way.