It's extremely rare that any rule, or any law, can be written to perfectly cover every unrelated situation that can be imagined. The NFHS Book is broken down into 10 separate rules, including Rule 2 that provides certain, specific, definitions.

For example Rule 6 relates to "Kicking the Ball & Fair Catch" while Rule 4 specifically addresses "Ball in Play, Dead Ball and Out of Bounds". Although there is logically an effort to establish some sense of consistency throughout the rules code, specific language used in one section may not exactly apply in all instances to the same language, or intent, established for another section.

Rule 2, "Definitions of Playing Terms" is designed to minimize confusion by limiting certain terms to very specific meanings, but does not intended to limit or specify the meanings of all words used throughout the code. Attempting to extract specific words or phrases from one section of the Rules and apply them to other sections may work in some instances, but then again, may not work at all in other circumstances.

As is often the case, in a variety of borderline circumstances, when logic may support one conclusion equally as well as another, the rule code arbitrarily accepts and establishes one conclusion over others as it may relate, specifically, to address a particular set of circumstances unique to that section of the general rules code.

A little, but mostly the differences are matters of taste & values. Traditionally NCAA has been more safety-conscious than NFL, and Fed more safety-conscious than NCAA, the idea apparently being that as players get older, more experienced, and fewer, they're selected for more injury resistance. Lately, however, NFL, thinking they have properties to protect, has gotten more safety conscious.

Robert