tensioner

Etymology tree
Proto-Indo-European *ten-
Proto-Indo-European *tend-der.
Proto-Italic *tendō
Latin tendō
Proto-Indo-European *-tis
Proto-Indo-European *-Hō
Proto-Indo-European *-tiHō
Proto-Italic *-tiō
Latin -tiō
Latin tēnsiōder.
Middle French tensionbor.
English tension
Proto-Indo-European *-yósder.
Proto-Italic *-āzijos
Latin -āriusnom.
Latin -āriusbor.
Proto-Germanic *-ārijaz
Proto-West Germanic *-ārī
Old English -ere
Middle English -ere
English -er
English tensioner
From tension + -er.