tau ‧ tol ‧ o ‧ gy /tɔːˈtɒlədʒi $ tɒːˈtɑː-/ BrE AmE noun ( plural tautologies ) [uncountable and countable] technical
[ Date: 1500-1600 ; Language: Late Latin ; Origin: tautologia , from Greek , from tautologos 'repeating things' , from tauto 'same' + legein 'to say' ]
a statement in which you say the same thing twice using different words in a way which is not necessary, for example, ‘He sat alone by himself.’ ⇨ redundant
—tautological /ˌtɔːtəˈlɒdʒɪk ə l◂ $ ˌtɒːtəˈlɑː-/ ( also tautologous /tɔːˈtɒləɡəs $ tɒːˈtɑː-/) adjective