Well, I reckon combat grade would refer to a category of a given item more suited to use in combat, such as in a war, or other similar conflict. While there wasn't much call for machetes in Iraq or Afganistan, there are places where a big blade that can do double duty as both a weed whacker and as a head lopper would be more desirable. Now, that is not to say that any decent machete can't be so utilized, but imho, combat grade would be a superior construction than the run of the mill variety, while not being incredibly more costly. This would mean better metal, thicker blade, slightly more agressive design, superior grip. A Khukri or Bolo would generally fit this category, being both suitable for heavy brush work and for melee. There are a whole host of other blade designs that fit this gendre, and so the term combat grade combined with machete seems to me to be appropos. Besides, I like multi-taskers, and while a thin flexible blade that is relatively soft is quite satisfactory for weed whacking, I would like something with a little more backbone to use for splitting wood, lopping hands and heads, and fending off other bladed attacks with a little more surety of non-failure.

I would say combat grade is significantly more specific in description than the term tactical. Based on how the industry uses that word, I have yet to be able to establish an effective definition for that term that wouldn't be all-inclusive.

Of course, marketing gurus will likely latch on to combat grade in much the same way I suppose. For now, though, it seems to be distinctive enough. Time will tell.