'Annam' originates from French (loanword) and ultimately from Sino-Vietnamese 'An Nam' (安南), where 'An' meant 'peace' or 'pacified' and 'Nam' meant 'south'.

'Annam' derived from Chinese/Sino-Vietnamese 'An Nan' (安南), was used in Vietnamese as 'An Nam', then adopted into French as 'Annam', and entered English usage from French.

Initially it meant 'peaceful/pacified south' as a place-name; over time it came to denote the political entity (the French protectorate) and more generally the central region of Vietnam.