tetramethyl

Etymology tree
Proto-Indo-European *kʷetwóres
Proto-Hellenic *kʷétwores
Ancient Greek τέσσᾰρες (téssăres)
Ancient Greek τετρᾰ- (tetră-)bor.
English tetra-
Proto-Indo-European *médʰu
Proto-Hellenic *métʰu
Ancient Greek μέθυ (méthu)
Proto-Indo-European *swel-der.?
Ancient Greek ῡ̔́λη (hū́lē)der.
German -yl
German Methylbor.
English methyl
English tetramethyl
From tetra- + methyl.