Ectoplasm

The closest thing to matter one can find when dealing with the ethereal. Ectoplasm interacts with matter in a limited fashion, leaving slime behind when one passes through the other.

As far as I know, this usage of the term originated with Ghostbusters, though I have seen it used now and again in other places since then.

As far as I know, the term originated from various early american mystics, who would secrete the substance when in their trances. There could be previous uses.

Ec"to*plasm (?), n. [Ecto- + Gr. form.] Biol. (a)

The outer transparent layer of protoplasm in a developing ovum

. (b)

The outer hyaline layer of protoplasm in a vegetable cell

. (c)

The ectosarc of protozoan.

 

© Webster 1913.