'spiny-headed' originates from the combination of 'spiny' and 'head,' where 'spiny' meant 'covered with spines' and 'head' referred to the top part of the body.

'spiny' changed from the Old English word 'spīnig' and 'head' from the Old English word 'hēafod,' eventually forming the modern English word 'spiny-headed.'

Initially, it meant 'having a head with spines,' and this meaning has largely remained the same in modern usage.