Metaphysical meaning of Tertius (mbd)
Tertius, ter'-ti-us (Lat.)--third; third part; threefold; three parts; triune.
The Holy Spirit, or Word in expression (third, the man who wrote for Paul his letter to the Romans). Expression is the third in the divine Trinity, as metaphysically understood--mind, idea, expression, mind referring to the Father-God, idea to the Son, Christ, or creative Word, and expression to the action of the Word, or Holy Spirit, in bringing forth into the outer that which has been idealized in Divine Mind.