Disambiguating taxonomies

D&D has a problem where it uses the same words to refer to monster types as well as specific families within those types. For example, the types dragon, elemental, giant and ooze are divided into "true" and "false" or "kin" families. The distinctions are often minor: "true" dragons have age categories, "true" elementals are amorphous blobs of one or more elements, "true" giants are prettier, and "true" oozes are fast moving. I'm going to devise some alternative terminology that is not ad hoc.

The Dragon type is divided into three broad categories: ametabolous, hemimetabolous, and holometabolous. Hemimetabolous dragons have age categories, ametabolous dragons do not. Holometabolous dragons are distinguished by immature forms that do not remotely resemble the mature forms (e.g. a human who becomes a dragon as they age).

ADDENDUM JULY 6, 2017: The "true" or "greater" dragons will instead be called "sectarian" dragons, as their identifier is that they are separated into different sects by their scale color.

The Ooze type is renamed to Blob type. It is divided into jellies, oozes, puddings and slimes, as well as the singularly bizarre "gelahedrons" (gelatinous platonic solids). Quoted from Hack & Slash:

Oozes are fast moving blobs, moving as fast as an unarmored man. They strike with a pseudo-pod lashing out and slamming into an opponent doing damage with acid and force 

Slimes are very very slow moving blobs, moving perhaps no faster than 1 foot an hour. They climb on high places and drop on unsuspecting adventurers. Their attack turns adventurers into slimes themselves.

Puddings are slow blobs that move along ceilings, walls, and floors [Roger says: "cohesive and rounded, moving by continuous traction."]. They attack by slamming acidic pseudopods against their opponents and engulfing prey. Certain attack methods and energy type can cause puddings to split. Puddings often have uneven opaque bubbly surfaces 

Jellies are sluggish blobs that move along floors [Roger says: "watery and flat, moving by pseudopod"]. They attack by slamming acidic pseudopods against their opponents and engulfing prey. Certain attack methods and energy type can cause some puddings to split. They often have smooth translucent surfaces.

The Elemental type is unchanged. The "[insert element] elemental" monsters are now generic elemental monster statistics rather than a family of their own. They exist not only to fill out the empty space in the monster and summoning lists, but like their alchemy and mythological inspirations come in every imaginable form to serve as a vessel for the DM's creativity.

The Giant type is unchanged. The ugly giants without "giant" in their name (e.g. trolls, ogres, ettins) are now collectively known as "Beast Giants" due to their bestial appearance in comparison to the pretty giants. This works by analogy with "beastmen" as a term for bestial humanoids.

And that's all I have to say about that.