Oxford Dictionary English shell suit noun noun BrE BrE//ˈʃel suːt// , BrE//ˈʃel sjuːt// ; NAmE NAmE//ˈʃel suːt// (British English) Add to my wordlistjump to other results a loose pair of trousers/pants and matching jacket worn as informal clothes. Shell suits are made of a light, slightly shiny, material and are often brightly coloured. compare tracksuitCheck pronunciation: shell suit oxfordlearnersdictionaries.com