'brightly-designed' is a compound word formed from 'brightly' and 'designed.' 'Brightly' comes from 'bright' (meaning 'full of light or color') with the adverbial suffix '-ly,' and 'designed' is the past participle of 'design' (meaning 'to plan or create').

'Brightly' comes from Old English 'beorht' (bright) and 'designed' from Latin 'designare' (to mark out, devise). The compound 'brightly-designed' is a modern English formation.

Initially, 'brightly-designed' simply described something designed in a bright manner, and this meaning has remained consistent.