'omnidirectionally' originates from English by adding the adverbial suffix '-ly' to 'omnidirectional'; 'omnidirectional' itself comes from the prefix 'omni-' from Latin 'omnis' (where 'omni-' meant 'all') combined with 'direction' from Latin 'directio'.

'omni-' derives from Latin 'omnis' meaning 'all', while 'direction' comes from Latin 'directio' (from 'dirigere', 'to direct'); these elements combined in Modern English to form 'omnidirectional', and the adverbial suffix '-ly' (from Old English '-līc' meaning 'like, having the quality of') produced 'omnidirectionally'.

Initially the components conveyed the idea of 'all' + 'direction' (i.e., 'toward all directions'); over time this became the single lexical item meaning 'in all directions' in modern usage.