Like any mechanical and physical entity there are scientific, industrial, and layman terminology.

Tankenstein (voiced by Derek Stephen Prince) - A powerful shapeshifting mechanical entity used by Astronema.

The newly spliced structure behaved as a single mechanical entity in all it's subsequent behavior, including an experimentally induced helix hand inversion during which all the cell filaments in the fiber's shaft unwound then twisted back together in the opposite helix hand.

The character races are rather unique in RPGs and include Bionecrons, Symbions and various cross-breeds between humans, animals and mechanical entities.

According to George Plimpton, his body becomes a huge, clanky, mechanical entity inhabited by Japanese admirals.

These mechanical entities are designed by Dr. Jango in his underwater base in the Pacific Ocean while being powered by Draias' minus energy.

As a mechanical entity, I have neither.

In E. M. Forster's 1909 novella The Machine Stops, humanity has been forced underground due to inhospitable conditions on Earth's surface, and is entirely dependent on "the machine," a god-like mechanical entity which has supplanted almost all free will by providing for humankind's every whim.

Fusion: The act of a natural or semi-artificial life-form entering the body of the mechanical entity and synchronizing with it to gain control, transforming the mechanical entity into humanoid form when doing so.

Presumably the seedship was built 'yesterday' but what 'yesterday' means to a mechanical entity could be anything to us.