One who or that which repeats. / (education) A student repeating a course or class. / (medicine) A patient who repeatedly presents with the same symptoms.

(chemistry) A specific arrangement of atoms that repeats within a macromolecule / (genetics) A specific sequence of bases that repeats within a nucleic acid (or of amino acids within a protein)

Capable of being replaced.

Anything that can be replaced.

(computer security) An attempt to subvert security by recording legitimate communications and repeating them to try to impersonate a valid user.

A commonly used description for law enforcement or help desk events.

(grammar, narratology) A form of speech used to express what another has said, often involving a change in tense.

A consequence or ensuing result of some action. / The act of driving back, or the state of being driven back; reflection; reverberation. / (music) Rapid reiteration of the same sound.

(transitive) To refill; to renew; to supply again or to add a fresh quantity to. / (transitive, archaic) To fill up; to complete; to supply fully.

That slows the penetration of water (but is not waterproof).