'unsegmentability' originates from English, specifically the elements 'un-' + 'segment' + '-ability', where 'un-' meant 'not', 'segment' derives from Latin 'segmentum' meaning 'a piece cut off', and '-ability' comes from Latin '-abilitas' meaning 'capability'.

'unsegmentability' developed in Modern English by adding the negative prefix 'un-' to 'segmentable' (adjective) and then the nominalizing suffix '-ity' to form the noun; 'segment' itself passed into English from Latin 'segmentum' (via Old French and Middle English) before becoming the base of these compounds.

Initially, the root 'segmentum' referred to 'a cut piece', and 'segment' came to mean 'a portion or unit'; over time the combined form 'unsegmentability' has come to mean 'the state of not being divisible into parts'.