The Semi-Subtle is the link between the Gross and the Subtle spheres.

Worldly people can never enter into communication with higher spirits, i.e. spirits belonging to the Subtle, Mental and Super-Mental spheres. For though the spirits of the Subtle and also, in some cases, of the Mental spheres, have to reincarnate, they don't have to stay in the Semi-Subtle sphere at any time. Spiritually advanced persons can, of course, communicate with advanced disembodied spirits, but they do not do so, for it is unnecessary. Spirituality has nothing to do with spiritism or communication with the spirits of the dead.


from notes dictated by Meher Baba, before March 1930, ST p8-9
Another version: Ms 2:3 p8-15, IL p18-21




There are three worlds or planes, and corresponding to them, there are three bodies, the Gross, the Subtle and the Mental. These worlds or planes should not be mixed up with the idea of place or sphere. The purpose of evolution is served with the attainment of the human form plus full consciousness. Simultaneous with the human body, the Subtle and Mental bodies make their appearance.

There is also another body, called the Astral body, which persists long after death, and belongs to the Sub-Subtle or lower of the seven regions of the Subtle plane. It is connected with both the Subtle and Gross planes or worlds. The Astral body is exactly the replica of the human body in all details. As is the Astral body, so will be the Gross body. The former is vapory or smoky in appearance, unlike the Subtle body, which has form, but no defined organs.


[link to www.meherbabadnyana.net]

semi-

1.half
2.partial, incomplete
3.somewhat, rather, quasi-

quasi-

Similar to, but not exactly the same as; virtual(ly). [from 17th c.]


[link to en.wiktionary.org (secure)]
[link to en.wiktionary.org (secure)]


Hardware virtualization


Concept

The term "virtualization" was coined in the 1960s to refer to a virtual machine (sometimes called "pseudo machine"), a term which itself dates from the experimental IBM M44/44X system.[citation needed] The creation and management of virtual machines has been called "platform virtualization", or "server virtualization", more recently.

Platform virtualization is performed on a given hardware platform by host software (a control program), which creates a simulated computer environment, a virtual machine (VM), for its guest software.


[link to en.wikipedia.org (secure)]

The gross body is actually kind of gross when you think about it.