The Trinity: What Are Key Terms?

It’s important to define the terms, so the rest of the doctrine of the Trinity can be clear—or clear enough.

Let’s begin.

1.. Where does the word Trinity come from?

It comes from the Latin word trinitas, meaning “threeness.” A better word is Tri-unity, which means “three in one.”

Fuller meaning of Triunity: Three persons (Father, Son, and Spirit) in one essence or one God.

2.. Is the word Trinity found in the Bible?

No, because the New Testament authors were engaged in other issues, like church life and salvation for Jews and gentiles. However, they assumed the reality of the Trinity, which is greater than a label.

Please see The Trinity: What Are the Basics?

3.. Are the words essence and substance and being interchangeable?

For our purposes they are, but some theologians, like Berkoff (p. 87), explain the fine nuances between the three terms. But let’s not get into them sine the website is basic.

In these posts on the Trinity I almost invariably use essence.

The meaning of essence is as follows:

God’s constitutional nature or his fundamental nature (Berkoff p. 87).

EDT (2nd ed.): “An essence consists in a thing’s most basic properties, what it is most fundamental” (p. 279).


By essence or nature is meant what something is, and essence is a set of characteristics—properties necessary to the thing … For example, it is necessary to the essence of a triangle that it has the following characteristics:

(1) It must have three sides

(2) It must have three corners or angles

(3) The sum of the three angles must be 180 degrees (p. 550, emphasis original)

Without those three properties, a triangle would not be a triangle, but something else. So now we can distinguish it from a square, for example.

Webster’s dictionary: “ultimate nature of a thing.”

4.. What does subsistence mean?

It means God’s mode of existing as Father, Son and Holy Spirit and how they operate between themselves and in relationship with humankind. It might be a rough synonym for existence.

Berkoff again:

To denote these distinctions [between God’s three persons] Greek writers generally employed the term hypostasis, while Latin authors used the term persona and sometimes substantia. Because the former was apt to be misleading and the latter ambiguous, the Schoolmen [Medieval scholars] coined the word subsistentia (p. 87).

Bottom line: subsistence can be often swapped out for person, and vice-versa, for our purposes here at this website. But modern theologians listed in the Sources, below, don’t use it much.

5.. What does person mean?

A living being who thinks, feels, and wills.


Personhood is traditionally understood as one who has intellect, feelings, and will. All three characteristics are attributed to all three members of the Trinity in Scripture. Essentially, personhood refers to an ‘I,’ a ‘who,’ or a subject. Each ‘I’ in the Trinity possesses (by virtue of its one common nature) the power to think, feel, and choose. Personhood itself is the I-ness or who-ness. (p. 541)

Translation: person means ‘I’ or ‘who,’ a living being, as distinct from a thing that can’t feel, think or choose. It means one who has mind, feelings, and will. All three persons of the Trinity have them. They are persons.

6.. What does attribute mean, and how does it relate to the Trinity?

Click on What a Divine Attribute Is

7.. Is there a summary of the uses of the terms?

Here is one:

Greek Latin English
One Ousia








Three Hypostaseis


Personae Persons


Modes of Subsistence

From Frame p. 482. These words are not biblical, for the Bible does not explain the Trinity formally and systematically; rather it assumes that Christ and the Spirit are fully God, and we have to draw conclusions from those verses. Yet there is nothing wrong with using those terms to clarify matters for the Church today.

Personae in Latin is plural for singular persona. Hypostaseis in Greek is plural for singular hypostasis.

8.. What does Godhead mean?

It is an old term for divine being or nature. It is often employed to show the divine nature with the three persons.

9.. What does the ontological Trinity mean?

Ontos means existence, and in this case it is used for the Trinity as he exists necessarily and eternally, apart from creation and humanity. It is what God essentially is, in relation to his nature and to the three persons—Father, Son, and Holy Spirit. Maybe we can understand the term by comparing it with the next term.

10.. What does the economic Trinity mean?

The term is used in its old sense, “ordering of activities.” This was used in the household, as well, ordering the full activities there.

It is the Trinity in relation to his creation and humanity, including the roles each person plays in redemption and providence.

So it describes the roles that the three persons have, while ontos (no. 9) describe God’s essence.

11.. What is a short definition of the Trinity, so we can keep things straight?

Please click on The Trinity: What Are the Basics?

But here is one for now:

There are three persons—Father Son, and Holy Spirit—who share the same essence as one God.

So how does knowing about the Trinity help me know God better?

Here is an entire ten-point post that answers that question:

The Trinity: What Does He Mean to Me?

As I write in every post: at Sunday morning church, where the laity is present, I suggest we teach the Trinity in relational terms. We have a relationship with the Father, through the Son, and by the indwelling and power of the Spirit.

May the grace of the Lord Jesus Christ, and the love of God, and the fellowship of the Holy Spirit be with you all. (2 Cor. 13:14, NIV)

This is how the NT presents God, and so do some places in the OT.  We can never give up on the three persons within One God. To do so would be to break our relationship with the three persons.


The Trinity: What Are the Basics?

The Trinity: What Are Key Terms?

The Trinity: What Are Some Illustrations?

The Trinity: What Does the Old Testament Say?

The Trinity: Three Persons Together in the New Testament

The Trinity: What Do Theologians Say?

The Trinity: What Are His Roles in Creation and Redemption?

The Trinity: What Does ‘Only Begotten Son’ Mean in John 3:16?

The Trinity: What Do Arians and Jehovah’s Witnesses Teach?

The Trinity: What Are Defective Ideas?

The Trinity: What Are Replies to Objections?

The Trinity: Why Would God Seem So Complicated?

The Trinity: What Does He Mean to Me?


Elmer Towns came up with this table, which shows that each person of the Trinity shares the same attributes as one God:


Attributes Father Son Holy Spirit


Jer 23:24 Matt 28:20 Ps. 139:7-12

(All Powerful)

Rom 1:16 Matt 28:18 Rom 15:19

(All Knowing)

Rom 11:33 John 21:17 John 14:26
Immutability (Unchanging) Mal 3:6 Heb 13:8 Hag 2:5
Eternality Ps 90:2 John 1:1 Heb 9:14
Holiness Lev 19:2 Heb 4:15 Name “Holy”
Love 1 John 3:1 Matt 9:36 Name “Comforter”
This list is far from exhaustive. Careful! Christ in his human nature was limited, but not in his divine nature (Towns p. 100)

Elmer Towns came up with this table too, which shows all three persons doing works that only God can:


Work Father Son Holy Spirit
Creation of World Ps 102:25 John 1:3 Gen 1:2
Creation of Man Gen 2:7 Col. 1:16 Job 33:4
Death of Christ Is 53:10 John 10:18 Heb 9:14
Resurrection of Christ Acts 2:32 John 2:19 1 Pet 3:18
Inspiration Heb 1:1-2 1 Pet 1:10-11 2 Pet 1:21
Indwelling of Believers Eph 4:6 Col 1:7 1 Cor 6:19
Authority of Ministry 2 Cor 3:4-6 1 Tim 1:12 Acts 20:28
Security of Believer John 10:29 Phil 1:6 Eph 1:13-14
This shows the unity of the Trinity. Each person of the Trinity contributed to each of these wonderful works, to God’s glory and for our salvation and redemption (Towns p. 100)


Works Cited

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