Both of these terms (hypostasis and essence), which are part of Orthodox triadology (teaching on the Holy Trinity) are, I discovered, found in the Greek New Testament (though used to address subjects other than God.) This gave me the opportunity to look up their etymology, and hopefully come to a better understanding of their original meaning.
Ousia - Apparently this is a feminine noun which means...
what one has, i.e. property, possessions, estate
It is the feminine form of the verb oan, which has the meaning of "being".
Hypostasis - While Strong's Greek-English concordance gives several definitions of this word, the most relevent that I could find was the following...
2. that which has foundation, is firm
a. that which has actual existence
1. a substance, real being
What I found interesting was that the King James Bible translates both of the passages these two terms occur in as "substance" (St.Luke 15:13 and Hebrews 11:1).
While I know "hypostasis" is commonly translated "person" in English (at least in the context of triadology) I've always been a bit hesitant with using that term, if only because of what I know of it's Latin origin. The word persona, in Latin, originally refered to the "actor's mask" - that is to say, the phenomenal experience of others, but implying that this is really only a part that is being played - it certainly did not refer to any objective, real existance. In fact, we have imported the word "persona" directly into English (what a hodge podge language we have!) to mean precisely this - we often speak of a man as having many "persona".
Another problem (or perhaps just a person scruple on my part) I have had with translating "hypostasis" as "person" without any qualification, is perhaps a more general problem we as a society have to contend with - just what is a "person"? Too often when you say "person", it gets saddeled with all sorts of anthropomorphic baggage, thoughts of physicality, etc... IOW not that which is really "essential" to being a "person", but what is really accidental to our being human persons. This is not good to bring into discussion about God, since only one of the Trinity (the Logos) became a man, and even this was without confusion of natures.
I'm curious as to whether others have dwelled on this subject before - is this just a strange scruple on my part, or is this really an important distinction to make?
Seraphim