'synarthrosis' originates from Greek, specifically the word 'συνάρθρωσις' (synarthrōsis), where 'σύν' (syn) meant 'together' and 'ἄρθρωσις' (arthrōsis) meant 'joint'.

'συνάρθρωσις' transformed into the Latin word 'synarthrosis' and eventually became the modern English word 'synarthrosis'.

Initially, it meant 'a joint together', and this meaning has largely remained the same in modern usage.