From Latin 'insignia' (distinguishing marks), from 'signum' (sign) — signs placed on a person to identify rank or office.
A badge or distinguishing mark of military rank, office, or membership of an organization; a distinguishing sign.
From Latin 'insignia,' the neuter plural of 'insigne' (a mark of distinction, a badge, a distinguishing token of office or honor), built from 'in-' (in, on, upon) + 'signum' (a mark, sign, signal, military standard, seal), from PIE *sekw- (to follow) in a specialized sense of something that shows the way, or possibly from *sek- (to cut, to mark by cutting). The root 'signum' is the source of 'sign,' 'signal,' 'signature,' 'significant,' 'signet,' and 'assign' (to mark out for someone). Insignia are the marks placed on a person or object to declare rank, office, or affiliation — a general's stars, a herald's coat-of-arms, a bishop's mitre, a scout's merit badges. The word entered English
English treats 'insignia' as both singular and plural, even though it is already a Latin plural (the singular is 'insigne'). You can say 'the insignia is' or 'the insignia are' — both are considered acceptable in modern English. This is similar to 'data' (Latin plural of 'datum'), 'media' (plural of 'medium'), and 'criteria' (plural of 'criterion'), where English speakers have largely forgotten or ignored the Latin number distinction.