Landmark envelopes are among some of the more well known brands in the industry, sitting pretty with others such as Harvard and Quality Park. Landmarks, by definition, are objects on land that have been deemed useful in relation to aiding some person or persons in gaining their bearings on the area, or in other situations, in relation to serving as a guide for said persons. Landmarks are often considered distinguished among their surroundings, which is effectively what allows them to be so useful as points of reference or interest. Landmarks are further discussed as being objects that would hold some importance or be considered valuable to someone, be it historic, of aesthetics, or cultural. In some contexts, a landmark can also be considered a point at which something was achieved during a process.
Looking at all of these possibilities, one could derive the meaning of the Landmark name as their brand being a cut above the rest, as standing out among the competition and being what people use to guide them forward. They consider their envelopes to be something of importance in the industry, something that other brands would look to for reference, for both the past and the future. And, as with some contexts of the definition, they consider their envelopes to be an achievement of the effort put into the creation process, something that others may be lacking in the industry.