I'm looking for a word for "All Being" to describe deity existing, always existing, and existing for eternity.
Other words often used to describe deity include:
None of these words describe a being/deity that has always existed and will always exist. A being that exists because he/she exists; i.e., needs nothing/nobody else to define his/her existence.
Does such a word exist?
This may verge into theology here; but if you want to talk about the relationship of a deity to time, one common word is eternal:
: having no beginning and no end in time : lasting forever
: existing at all times : always true or valid
(merriam-webster.com)
Saint Thomas Aquinas, in his Summa Theologica, defines eternity (following the Christian philosopher Boethius) as
the simultaneously-whole and perfect possession of interminable life
and argues that this characterizes God.
If this is what you're looking for, use the word eternal.
It is not clear why eternal or everlasting wouldn’t be good enough as is, but if you want a higher-falutin’ term, the most obvious answer is sempiternal, which the OED defines as:
Enduring constantly and continually; everlasting, eternal.
That takes the Latin semper meaning “ever” or “always” and combines it with ‑ternal to produce a fancy word meaning “everlasting”.¹
The OED also attests the adjective ever-being with the sense “that which always is”, although the resulting noun everbeingness the OED considers obsolete.
A rather less common word with the same meaning as sempiternal is aeviternal (also spelt æviternal), which the OED defines as:
Everlasting, endless, eternal.
This time it comes from aevum meaning “an age”, which is related to aeon (sometimes spelt æon or eon) and thence to Greek αἰών.
This is related to but different from longeval (also spelt longaeval or longæval), which just means long-lasting or long-lived, not ever-lasting or ever-living. But you can see the same aevum root at work, this time at the end of the word instead of at its beginning.
The word omniessent (also spelt omni-essent or omniëssent) that was kindly suggested by Janus in a potentially ephemeral² comment is simply the adjective corresponding to the noun omni-essence, which the OED defines as:
universal essence or being
To me omniessent more suggests ubiquity of being than it does omnitemporaneity of the same.
Speaking of omnitemporaneousness, that brings me to my final entry, omnitemporal, defined by the OED as:
relating to all times; including in its meaning all the various tenses
These are all long and highly fancy — perhaps even fanciful — words built of Latinate roots from antiquity instead of being built of native roots the way everlasting and everbeing are.
As such, they might have a place in a lofty register such as that of Aquinas, but for more casual ones, simpler words are likely better.
Footnotes:
One should take some care not to confuse sempervirent with sempervivent, where the latter means “everliving” or “lives-forever”, a term once applied to the succulent we call hen-and-chicks or houseleek and which survives as the genus Sempervivum.
RHK Webster's has:
Immanent: 2. (of the Deity) indwelling the universe, time, etc.
I have often heard unbegotten used in this context (could not link to Oxford as that word is behind a pay-wall on their site.)
It literally means that one was not born or created, thus implying they have always existed. I see the word often used in the British Anglican church to describe God in particular but is equally applicable in any religion.
This word also very well emphasizes the not needing anyone else to exist part by explicitly meaning they had no creator by definition. It also has religious connotations, perhaps making it more appropriate here also.
To provide some examples (borrowed from the Oxford English Dictionary):
We know there is one God, alone unbegotten, alone eternal, alone without beginning, alone true, alone immortal.
And:
The personae are distinguished by their difference in origin: the Father unbegotten, the Son begotten, the Spirit proceeding.
yes, and you already said it - omnipresent.
Definition 3 of transcendent at Dictionary.com is
transcending the universe, time, etc. Compare immanent (def 3).
