*exogen*

a. 1. (Bot.) derived from or originating outside; pertaining to, or having the character of, an exogen; -- the opposite of endogenous.
Syn. -- exogenetic. [ 1913 Webster ]

2. (Bot.) Growing by addition to the exterior; growing by addition of a new external layer of cells on the surface just beneath the bark; -- of plants. [ 1913 Webster ]

3. (Anat.) Growing from previously ossified parts; -- opposed to autogenous. Owen. [ 1913 Webster ]

4. (Med.) caused by factors from outside the body, rather than from an abnormality of internal functions; -- of illness. [ PJC ]

5. (Biol., Biochem.) not synthesized within the organism; absorbed or assimilated from outside the organism. [ PJC ]

Exogenous aneurism (Med.), an aneurism which is produced by causes acting from without, as from injury. [ 1913 Webster ]