'excitability' originates from Latin, specifically the verb 'excitare', where the prefix 'ex-' meant 'out' or 'forth' and 'citare' (a frequentative of 'ciere') meant 'to set in motion' or 'to rouse'.

'excitare' gave rise to Late Latin forms such as 'excitabilis' and Medieval Latin 'excitabilitas', and the modern English noun 'excitability' developed from these Latin roots through scholarly and scientific usage.

Initially it meant 'the ability to be roused or called into action'; over time the sense broadened to include a technical physiological meaning (responsiveness of tissues) and a general psychological meaning (tendency to become emotionally excited).