What's the difference between epenthesis and tmesis?

Epenthesis

Definition:

• (n.) The insertion of a letter or a sound in the body of a word; as, the b in "nimble" from AS. n/mol.

Example Sentences:

Tmesis

Definition:

• (n.) The separation of the parts of a compound word by the intervention of one or more words; as, in what place soever, for whatsoever place.

Example Sentences:

• (1) A case of traumatic hemisomato-tmesis is presented.