'custom-assembled' originates from the combination of 'custom,' meaning 'made to order,' and 'assemble,' meaning 'to put together.'

'custom' and 'assemble' were combined in modern English to form 'custom-assembled,' reflecting the process of assembling items to specific requirements.

Initially, 'custom' meant 'made to order,' and 'assemble' meant 'to put together.' The combination retains the original meanings, emphasizing the tailored assembly process.