I’m sure you know what a candidate is – someone who’s being considered for a job, position, award, honour, and so on. It doesn’t always have to be a person either, for example, ‘that wall is a prime candidate for a fresh coat of paint’ (said no-one ever, but you get the idea). But, why are these people (and walls) called candidates?
As usual, we need to take a quick trip back to ancient Rome for the answer. ‘Candidate’ comes from the Latin word candidatus, which literally means ‘clothed in white’. That’s because in ancient Rome, men running for public office (and it was only men, sadly – women were legally barred from holding public office, voting or joining the Roman Senate) wore a special bright-white toga called a ‘toga candida’. This brilliant white wool was supposed to symbolise purity, honesty and transparency of intention. Hmmm. The toga's name came from the Latin verb candere, meaning ‘to shine’ or ‘to be glowing white’ – that’s also where we get words like ‘candid’ and ‘candle’ from.
Someone wearing this white toga was referred to as a candidatus AKA ‘a white-robed person’. Over time, we stopped using the term to describe the clothing and started using it to refer to the person seeking office themselves. ‘Candidate’ entered Early Modern English in the 17th century straight from the Latin, eventually broadening to mean anyone applying for a position, award or political office.
(Slightly unpleasant aside – if you’ve ever had thrush, you might know that the fungus that causes it is called ‘candida’. That also comes straight from candidus, due to the fact that it grows in creamy-white colonies. Yuck. Thrush’s full Latin name is Candida albicans, with albicans coming from the Latin albicō meaning ‘to become white’. So that means our fungus is effectively called ‘whitey white’. I do love an etymology tautology.)