(Paraphrased excerpts taken from Occult Glossary, Word Wisdom, and The Esoteric Tradition by G. de Purucker)
Any human LIFE CENTER exists before embodiment
General term for the belief that the human soul existed before it was born on earth, and did not come into being for the first time with its present earth life.
Any LIFE CENTER in any body on any plane
Expresses more than that the soul merely pre-exists. It expresses the idea that the soul takes unto itself a succession of new bodies on whatever plane it may happen to be on. The specific significance is that of assuming new embodiments periodically. It does not indicate that the body is taken here on earth or elsewhere, or whether the body be visible or invisible. Any LIFE CENTER reimbodies itself, and the term is not limited to humans.
Any LIFE CENTER in new body on any plane
General term signifying that a LIFE CENTER is coming into birth again, and takes unto itself a new body, excluding specific explanations of the type or kind of reimbodiment.
Any LIFE CENTER in an identic strain
From the Greek, meaning 'coming again into being' or 'becoming again.' The transmission of an identic life in cyclical, recurring phases. (i.e.; From an oak tree, to its seed or acorn, to a new oak tree.) It signifies the continuous transmission of an identic life, producing at each transformation a new manifestation or result, these several results being in each case a new becoming of the same life-stream. This is quite different from transmigration.
[The words above signify aspects or phases of the general doctrine of reimbodiment. The post-mortem destiny of most of the reimbodying egos, or LIFE CENTERS, actually includes not merely one, but all of these phases.]
Any LIFE CENTER into a similar or differing strain, or one condition, state or plane to another
It means that the particular life-atoms, which in their aggregate compose a man's lower principles, at and following the change that men call death, migrate or pass into other bodies to which these life-atoms are attracted by similarity of development. (Does not mean LIFE CENTERS change into other LIFE CENTERS either above or below between lives -- i.e.; humans do not reimbody as animals, etc.) The human LIFE CENTER passing from one condition or state or plane, to another, within its karmic evolutionary path.
Any LIFE CENTER between life-periods
From the Greek, meaning 'insouling after insouling' or 'changing soul after soul.' A LIFE CENTER, during the course of its evolutionary peregrinations, throws forth from itself periodically a new 'soul garment' or 'soul sheath'; a series of soul-changings as the ages pass by.
Any LIFE CENTER (usually human) in a fleshy body composition
From the Latin, meaning 'reinfleshment.' The coming again into a fleshy body of a soul of the same type -- usually applied to the human soul and body. (To try and clarify things some have proposed the following terms for reimbodiment of distinct LIFE CENTERS; Reinzooination for animals, Reinvegetalization for plants, and Reinmetalization for minerals.) The term also contains the implication of possible incarnation in flesh of entities which have finished their earthly evolution, but who choose to return for the purpose of aiding their less evolved brothers. Please note that resurrection is a form of reincarnational belief.
Any human LIFE CENTER in a different body composition
From the Greek, meaning 'changing body after body,' not necessarily always using human bodies of flesh, but bodies of appropriate yet different physical material concordant with the evolutionary stage of development with the plane or sphere of Nature on which the reimbodiment takes place. In far past ages the human race had bodies, but not of flesh, as may be the case in far distant ages of the future. May be termed as 'bodifying' -- whatever that 'body' may be composed of.
Each of these eight terms has specific meaning. G. de Purucker gave the following example of usage in The Esoteric Tradition, 2:601-2:
"Thus: the human soul not only 'pre-exists' but it 'reimbodies' itself, and in doing so takes 'rebirth' on this Earth, and it does so by means of psycho-astral 'palingenesis,' accomplished by means of its own particular manner of 'transmigration,' the whole process largely being marked by the 'metempsychosis' through which it passes, bringing about 'reincarnation' or returning to human fleshly bodies on Earth, thus filling its need for 'bodifying' its faculties and attributes in this sphere."