Originally referring to the rapids (Imatrankoski); ultimate origin unknown (possibly from a lost substrate). According to Viljo Nissilä, the name may derive from earlier *Imantero or *Imanteri, perhaps from a lost given name ultimately derived from imeä.[1] Alternatively, according to Pauli Rahkonen, possibly (although not certainly) from a Uralic (Meryan-East Chudian) substrate language, where the initial component may derive from *emä(“mother”) and the latter -dra derives from *jädrä, from *jäwrä(“lake”); thus the name would initially have referred to the lake Saimaa.[2]
The external locative cases (adessive, allative and ablative) are used with this place name when referring to a location; for example, "in Imatra" is Imatralla.
^ Sirkka Paikkala, editor (2007), Suomalainen paikannimikirja [Book of Finnish Place names] (in Finnish), Helsinki: Karttakeskus, Kotimaisten kielten tutkimuskeskus, →ISBN
^ Rahkonen, Pauli. Suomeen suuntautuneiden nimistövirtausten monimuotoisuus. Muinaistutkija 1/2021. p. 18, 27–28