Protective suit

Protective suit was what Barbara Wright termed the distinctive black bodysuit used by the Voord, which was similar to a frogman's wetsuit and flippers.

Early history
The Voord suit tended to be effective protection from hostile elements. It was not, however, completely impermeable. Barbara once discovered an empty Voord suit with two puncture marks, suggesting that the acid had consumed the Voord within. The Voord were also armed with commando-style knives.

Still, the shape of the suit suggested a few things about basic Voord anatomy. They were, for example, humanoid. And they had three appendages on their heads — a thin stick with a circle at the front and two loop-like horns on the side. Nevertheless, not all Voord had these cranial appendages. Yartek, the leader of the Voord on Marinus, only had two appendages, one on the right and left of his head. (TV: The Keys of Marinus)

Using these, the Voord were capable of telepathically communicating with each other. The leader had the higher intelligence and was able to control others with this organ. They could also control the minds of the Fishmen, but they could not read the First Doctor's mind. If this organ was damaged or removed, the Voord would be rendered senseless. (PROSE: The Fishmen of Kandalinga)

The Voord mask fused with the wearer and usually could not be removed without killing them. The mask gave the Voord their telepathic abilities. Native Voord were given their masks in a ceremony when they achieved maturity. (AUDIO: Domain of the Voord)

On planets they conquered, the Voord converted the natives into Voord creatures by fusing them with Voord masks and suits — the mask tested their loyalty to the Voord, and if they were found disloyal, they were killed. While indistinguishable from the outside, unlike the native Voord of the Blood Tree, the converted Voord creatures had much less autonomy, and were mostly puppets of the native Voord commanders. The Voord suits lengthened their lifespans to a thousand years. (AUDIO: Domain of the Voord)

Cybermen
On Marinus, the Voord began experimenting with a Worldshaper, which accelerated time locally and "quick-evolved" the Voord. Over time they replaced their body parts with cybernetic parts. The Sixth Doctor, Frobisher, Peri Brown and Jamie McCrimmon attempted to stop the Voord. Jamie sacrificed himself to destroy the Worldshaper, which caused a blast that accelerated time. The Voord then evolved into entirely cybernetic creatures called Cybermen, their protective suits becoming Cyber-suits. (COMIC: The World Shapers)

Time War
During the Last Great Time War, the Voord were mutated by paradoxes and shifts in causation. They became more muscular and their bodysuits. Following the War, a bodysuit was worn by an alternate version of the Twelfth Doctor. (COMIC: Four Doctors)