7.22: "outflanked": two or more combat units are attacking the defending hex through opposite hexsides.
I.e. something like 2 attackers "A" attacking a defender "D":
. A . .
. D . .
. . A .
The definition excludes a different configuration which seems like it perhaps should be considered "outflanked" to me; is it intentional that the following "3 attackers in a ring" situation is not "outflanked"?
. A . .
. D A .
. A . .
I'd expect some definition like (e.g.) "outflanked": all hexes around the defender are occupied by or adjacent to attacking units. (This includes all cases covered by the published rule, as well as allowing additional cases like the 3-in-a-ring example.)
Pondering implications at the map edge of the published rule and the alternative idea:
The rule as written implies a defender on alternating ("protruding") hexes of the western or eastern map edge (or in a map corner) cannot be outflanked while on the other alternating ("non-protruding") hexes of the western or eastern map edge adefender can be out flanked. And a defender on any (non-corner) hex of the northern or southern map edge can be outflanked.
My hypothetical alternative rule permits defenders on any edge to be outflanked. If that's not desired, it could say "6 hexes around the defender are occupied by or adjacent to attacking units", which would similarly make all map edges work the same: outflanking is then not possible at any map edge...