The Spanish word 'mochila' (backpack) has an interesting journey through multiple languages. It starts with the Latin word 'mutilus' meaning 'mutilated' or 'cropped'. This word influenced the Basque term 'motxil', which meant 'young boy' or 'servant'. The word then entered Spanish as 'mochil' meaning 'servant boy', and with the addition of the feminine noun suffix '-a', it evolved into 'mochila'.

The semantic evolution from 'servant boy' to 'backpack' likely comes from the association with the bags or packs that servant boys would carry to perform their duties. Over time, the word came to refer to the bag itself rather than the person carrying it.

While 'mochila' itself is a common Spanish word, the older form 'mochil' (meaning servant boy) is now obsolete in modern Spanish. However, you might encounter related words like 'mocho/a' (meaning cut off or cropped), which connects back to the original Latin 'mutilus'.

The Latin root 'mutilus' is also the source of the English word 'mutilate'. While 'mutilate' has retained its original meaning of cutting or damaging something severely, its Spanish cousin 'mochila' took a very different semantic path to become the common word for backpack.