noun
dumbbell
Standard word for a dumbbell used in weight training.
毎朝アレイで筋トレをしている。
I do strength training with dumbbells every morning.
Variant ateji; very rare.
ダンベル is a more common loanword from English 'dumbbell', while アレイ is an older ateji-based term still understood but less frequent.
Ateji (当て字) from 亜 (a) and 鈴 (rei), chosen for their sounds rather than meanings. The word is a Japanese coinage for 'dumbbell'.