Why was "tantrum" trending last week?
"redundancy in words," 1580s, from Late Latin pleonasmus, from Greek pleonasmos, from pleonazein "to be more than enough, to be superfluous," in grammatical use, "to add superfluously," from comb. form of pleon "more" (see pleio-).
pleonasm ple·o·nasm (plē'ə-nāz'əm)
An excess in the number or size of parts.