meaning of preemption
1. The act or right of purchasing before others.
2. The privilege or prerogative formerly enjoyed by the king of buying provisions for his household in preference to others.
3. The right of an actual settler upon public lands (particularly those of the United States) to purchase a certain portion at a fixed price in preference to all other applicants.
4. a prior appropriation of something; "the preemption of bandwidth by commercial
">interests"