'solid-colored' is a modern English compound formed from the adjective 'solid' + the past-participial adjective 'colored' (i.e., 'having color'). 'Solid' ultimately comes from Latin 'solidus' and 'color' from Latin 'color'/'colorare'.

'solid' came into English via Old French 'solide' from Latin 'solidus'; 'color' entered English via Old French 'colour' from Latin 'color'. The compound adjective 'solid-colored' developed in modern English (notably in American English) to describe items of a single hue.

The components originally referred to physical solidity ('solid') and hue ('color'); combined, the phrase evolved to mean 'having one uniform color' rather than implying physical solidity.