'ingress' originates from Latin, specifically the word 'ingressus', where 'in-' meant 'into' and 'gressus' (from 'gradi/gress') meant 'to step or go'.

'ingressus' passed into Medieval Latin and then Middle English (as forms like 'ingresse'), and eventually became the modern English word 'ingress'.

Initially it meant 'a going in' or 'the act of stepping in', but over time it broadened to include legal senses ('right of entry') and technical senses (e.g., network 'ingress' meaning incoming traffic).