There are still at least two places in this state where
the Sacred Species in the Roman Church are paraded, as
per ancient custom, for the adoration of the congregants.
When taken out into the fields four acolytes hold poles
which support a baldachin over the priest and the
ostensorium as the procession moves to its destination.

ostensorium ? What is this, please?

That must be a box or chest where they keep holy bones or bones that are considered as such. Holy bones! Holy smoke!

It's a box holding the host.

It's a box holding the host.

AKA a monstrance. The former is being "seen" and the latter is being "shown".

Don't forget the architectural meaning, wherein the temporary cloth canopy is replaced with permanent materials, most famously, Gianlorenzo Bernini's glorious Baldacchino in St. Peters, Rome.

Interestingly, in the source you cite from Der Spiegel, describing a Jewish wedding, the Hebrew term for the marriage canopy, the Chuppah, has been translated as baldachin, a rendering I've never seen before.

host (n.3)
"body of Christ, consecrated bread," c.1300, from L. hostia "sacrifice," also "the animal sacrificed," applied in Church Latin to Christ; probably ultimately related to host (n.1) in its root sense of "stranger, enemy."

host- army , host -hostile- -

Sorry, my knowledge of those ritual details is sub zero.