'Zyzzyva' – a tropical beetle – has become the new last word in the Oxford English Dictionary with the latest quarterly update which added over 1,200 new words, phrases and senses.

Until now, the last alphabetic entry in the Oxford English Dictionary (OED) was zythum, a kind of malt beer brewed in ancient Egypt.

The title now belongs to Zyzzyva, the name of a genus of tropical weevils native to South America and typically found on or near palm trees.

The name of the genus was coined by the entomologist Thomas Lincoln Casey in 1922.

“The motivation for the name is not clear,” Katherine Connor Martin, Head of US Dictionaries said in a blog post.

“Some sources suggest it is an onomatopoeic reference to the noise made by the weevil, possibly inspired by a former genus of leafhoppers, Zyzza, and perhaps chosen deliberately as an alphabetical curiosity,” she said.

Oxford's 2016 word of the year 'post-truth' is also entered in the OED update.

Defined as 'relating to or denoting circumstances in which objective facts are less influential in shaping political debate or public opinion than appeals to emotion and personal belief,' it evidences an emerging use of post prefix forming words denoting that a specified concept has become unimportant or irrelevant.

Earlier words using post in this way include postnational and post-racial.

The update also included a new sense of the noun 'thing'.

The word has been part of the English lexicon for more than a thousand years, but the OED now defines a new meaning which has only arisen in the past two decades.

The new sense is defined as 'a genuine or established phenomenon or practice,' and is often used in questions conveying surprise or incredulity, such as 'is that even a thing?'

The earliest citation is from 2000, in an episode of the US television programme 'The West Wing': “Did you know that 'leaf peeping' was a thing?”

The update also included the term 'Boston marriage' used to describe the cohabitation of two women, especially in a romantic relationship or intimate friendship – a living arrangement that was an acknowledged cultural phenomenon among unmarried, well-to-do American women in the late 19th century.

The depiction of such a relationship in Henry James's novel The Bostonians (1886) may have inspired the term, or it may be that both the term and the title of the novel allude to the prevalence of such cohabitation in the city of Boston.
The OED's earliest evidence for the usage comes from an 1893 letter to the editor of the progressive journal Open Court by the Beacon Hill-born reformer and suffragist Ednah D Cheney.

Cheney wrote that she 'for many years has been accustomed to the existence of ties between women so intimate and persistent, that they are fully recognised by their friends, and of late have acquired, if not a local habitation, at least a name, for they have been christened “Boston Marriages”'.

She goes on to say that although she would not go so far as to suggest that Boston marriages be 'adopted into our civil code, still 'this institution deserves to be recognised as a really valuable one for women in our present state of civilisation.'

The OED publishes four updates a year. The next update will be added to the dictionary in September 2017.