autogenic

As a letter s

is the letter s with a.

As an adjective autogenic is

self-produced.

As an adjective autogenic

is self-produced.

As a noun null is

zero, nil; the cardinal number before einn.

As an adjective autogenic

is self-produced.

As a noun allograft is

(surgery) a surgical transplant of tissue between genetically different individuals of the same species; a homograft or homotransplant.

As adjectives the difference between autogenic and undefined

is that autogenic is self-produced while undefined is lacking a definition or value.

As adjectives the difference between autogenic and allogeneic

is that autogenic is self-produced while allogeneic is genetically different because of being derived from separate individuals of the same species.

As adjectives the difference between autogenic and allogenic

is that autogenic is self-produced while allogenic is having an external cause, or source; exogenous.