'encoder' originates from the word 'encode', which is derived from the prefix 'en-' meaning 'to cause to be in' and the root 'code', which refers to a system of symbols or signals.

'encode' transformed from the combination of 'en-' and 'code', and eventually became the modern English word 'encoder' to describe a device or process that performs encoding.

Initially, 'encode' meant 'to convert into a coded form', and this meaning has largely remained the same in modern usage.