Demihuman

Demihuman is a term adopted into the /tg/ lexicon from Dungeons & Dragons prior to 3rd edition. It referred to "those nonhuman humanoid races you can play in-game" - that is, those in such parties as Tolkien would assemble, the elf, dwarf, and halfling. Other races, such as orcs, goblinoids, kobolds, xvarts, ogres and so forth were all lumped together as basic "humanoids" which you had to fight. AD&D also allowed the gnome (which was fine) and the half-orc (stretching the concept).

E. Gary Gygax, designing a human-centered Robert Howard style of game, had problems with the whole notion of nonhuman PCs, to the extent they had abilities we don't and might force a world of human inferiority - in which world, many human players wouldn't play a human. Thus his rules tried to nerf them in several ways, depending on the version of D&D you were playing. Basic Dungeons & Dragons used the "race-as-class" system, where playing a non-human was in effect the same as playing a specific class as a human, so your demihuman abilities were very strictly defined and often not as good as the closest human counterpart. Advanced Dungeons & Dragons flat out mandated you had to have a specific Ability Scores set to be allowed to play a demihuman (but then, they also demanded the same for classes), and likewise restricted what classes those races could have, and what level they could reach in that class - in effect, the core demihumans were restricted to the Fighter, Wizard, Rogue and Cleric classes, and even then would cap out well before a human would. The only benefit demihumans universally got was a much simpler form of multiclassing, and even with its hassling rules, dual-classing was still better because it recognized the Linear Warriors, Quadratic Wizards problem.

Yes, that's right; in AD&D, humans made better wizards than elves or gnomes, and neither elves nor their half-human spawn could be bards.

But the rest of D&D's designers, for better or worse, looked at what Gygax had decreed and collectively decided "Buddy, that's bullshit". As AD&D went on, new races and demihuman subraces were introduced that had broader class compatibilities and class level caps, whilst BECMI would use the Known World Gazetteers to provide rules so that demihuman PCs could properly reach for Immortality alongside their human peers. Settings would introduce variant rules that modified existing demihumans, such as Al-Qadim being the first setting to let you play a dwarf wizard. Kits were invented to let demihumans at least emulate the likes of the druid, bard and paladin. Then the GAZ10 allowed for full-on orc PCs, and hobgoblins and gnolls and whatever else, which opened the floodgates and led to books like the Complete Books of Demihumans and Humanoids. And then there came From The Ashes, for good or for ill. So much for all that, then.

With the release of 3rd edition, this whole term was dropped from the official D&D lexicon. Some suspect worries over its hidden assumptions; using "demihuman" to refer to playable humanoids could be taken to imply that 1) all civilized/nonevil humanoid races are related to humans, and 2) those races are somehow inferior to "real" humans, while "humanoids" are shittier still. Note that neither of these assumptions are at all true in most D&D settings, despite what most editions' crunch would have you believe. And anyway even before 2e, the Humanity Fuck Yeah skiff had long floated down the Svartjet to get pegged by drow.

Still, the term does occasionally pop up; aside from the obvious nostalgia appeal, the plain truth of the matter is that "demihuman" is a simple shorthand way of referencing all of the "traditionally non-evil humanoid races" with a single word. And what fa/tg/uy is opposed to the idea of having a shorthand name to call something, really?

Anime has resurrected "demihuman" for monstergirls, especially for human-mammal mixes like kitsune and catgirls. Minotaurs would probably count but since they're bigger than us, they don't usually feature.