古埃及神经常以三为单位出现，如阿蒙-拉-普塔、凯普利-拉-阿图姆等。学者们对这种现象的称呼并不统一，有“三位一体”（trinity）和“三个一组” （triad）两种说法。“三个一组”指的是古埃及“三个一组”神，泛指所有由三个神（或其中之一为法老）构成的组合，包含成员间具有亲缘关系和不具有亲缘关系两种情况；“三位一体”指的是古埃及“三位一体”神，特指由三个不具有亲缘关系且能形成封闭系统或是某种特质三个方面的神所构成的组合，属于“三个一组”的子范畴。古埃及宗教中的“三位一体”不能理解为基督教的“三位一体”学说，本文引入这一概念是为了和具有亲缘关系的“三个一组”神区分开来。

古埃及“三个一组”神的分类如下：依据内容存在跨越性别和未跨越性别两种类型；依据性质存在“神格唯一”和“三位异体”两种类型。普塔-索卡-奥西里斯是包含三位男性神，未跨越性别且“神格唯一”的“三个一组”神。这种“三个一组”神在古埃及宗教研究的语境下可以称作“三位一体”神。

古埃及人创造复合神最常用的方法是把几个神的名字连起来。普塔-索卡-奥西里斯是非常典型的复合产物，这一复合神由普塔神、索卡神和奥西里斯神结合形成。古王国第6王朝萨卡拉的墓室铭文出现“普塔-索卡”字样，说明这一时期普塔神已经和索卡神进行了结合；中王国第12至13王朝的石碑上出现“普塔-索卡-奥西里斯”字样，证明这一时期普塔-索卡-奥西里斯的组合已经出现。古埃及祭司出于利益考虑会使神与神之间等同，普塔神、索卡神和奥西里斯神之间的相互等同最终使三者结合成为普塔-索卡-奥西里斯。鉴于普塔-奥西里斯组合的出现晚于普塔-索卡-奥西里斯，三神结合的过程可能是普塔神和索卡神等同形成普塔-索卡；索卡神和奥西里斯神等同形成索卡-奥西里斯；普塔-索卡结合奥西里斯神形成普塔-索卡-奥西里斯，等同的原因是三者在 职能方面存在共同点。

古埃及“三个一组”现象和基督教“三位一体”的相似之处在于二者都通过“三”和“一”的关系实现了统一与多元之间的转化，而基督教在这一点上可能是受到了古埃及神学的影响。

The ancient Egyptian deities often appeared as a combination of three gods, such as Amun-Ra-Ptah, Khepri-Ra-Atum and so on. When talking about this phenomenon, some scholars use the word “trinity”, others use the word “triad”. To study this phenomenon in ancient Egyptian religion, we need to make a distinction between the two words mentioned above. The word “triad” refers to all groups composed of three deities (one of them can also be a pharaoh). Those members either have kingship or not. The word “trinity” especially refers to groups composed of three deities who don’t have any kingship and can form a closed circulation at the same time or they represent one attribute. This kind of group belongs to the subcategory of “triad”. However, the Egyptian “trinity” should not be understood as the Christian idea of the trinity. We use this conception only to distinguish Egyptian “trinity” from “triad”.  

The classification of Egyptian triads is as follows: According to the gender of members in a group, we can divide them into two types: triads which consist of different genders and of the same gender; According to the nature of members, we can also divide them into two types: triads of a modalistic conception and triads of a tritheistic structure. The latter in the context of studies of ancient Egyptian religion can be called “trinity”.

The ancient Egyptians generally create composite god by putting their names together. Ptah-Sokar-Osiris is exactly a typical composite god formed of three deities: Ptah, Sokar and Osiris. On an Old Kingdom stele in the tomb of Shepsesptah at Sakkara, we can see an inscription about Ptah-Sokar, which means the combination of Ptah-Sokar have already existed during this period. On a Middle Kingdom stele, we can see an inscription about Ptah-Sokar-Osiris, which means Ptah Sokar and Osiris have combined during this period. Ancient Egyptian priests often identified one god with another out of their interests. The combination of Ptah Sokar and Osiris may be attributed to the identification between these three deities. Considering the fact that the group of Ptah-Osiris appeared later than the combination of Ptah-Sokar-Osiris, the god Ptah might be identified with Sokar and then combined with him; the god Sokar might be identified with Osiris and then formed Sokar-Osiris; the god Ptah-Sokar may be identified with Osiris and finally became the god Ptah-Sokar-Osiris.

The similarity between the ancient Egyptian "triad" and the Christian "trinity" is that they both achieve the transformation between unity and plurality through the relationship of "three" and "one". In this regard, Christianity may be influenced by the ancient Egyptian theology.