Supplement \Sup"ple*ment\, v. t. [imp. & p. p. {Supplemented};
p. pr. & vb. n. {Supplementing}.]
To fill up or supply by addition; to add something to.
[1913 Webster]
Causes of one kind must be supplemented by bringing to
bear upon them a causation of another kind. --I.
Taylor.
[1913 Webster] Supplemental