We have all heard, and likely used, the term millennial, but if pushed, do you know exactly which ages fall into the millennial age bracket? It becomes a little more complicated when the new term "geriatric millennial" is thrown into the mix. But what is exactly that? According to the most straightforward definition, millennials, also known as Generation Y or Gen Y, are the age group that follows Generation X and precedes Generation Z. When it comes to exact numbers, it's a little less specific, but it is generally agreed those born between 1980 and 1996, aged 24 to 41, fall into the millennial generational bracket, with the oldest in the demographic coming of age around the millennium celebrations in 2000. The elder tier of millennials, those born between 1980 and 1985, fall into the micro-generation category of geriatric millennials, a turn-of-phrase that has left people reeling on Twitter. These are people who are likely still renting a home, use Facebook and carry an iPhone in their pocket. They are digitally savvy, but also remember fighting siblings for a slot on the family computer, having to come offline when their mum wanted to make a phone call and spending Friday nights browsing the shelves of Blockbuster to pick a VHS to take home. True as it may be that there is a world of difference between the childhoods of those born in 1980 and 1996, it's the use of the word "geriatric" and the fact it's been applied to people aged 35 to 41, that's sparked a reaction. Meena Harris, 36, author, lawyer and niece of US Vice President Kamala Harris, joked on Twitter that she "rejects and denounces the term geriatric millennial". The term has been newly popularised by author Erica Dhawan in a <a href="https://index.medium.com/why-the-hybrid-workforce-of-the-future-depends-on-the-geriatric-millennial-6f9ff4de1d23"><i>Medium</i></a> article published in April. The piece aims to create a smoother bridge between the first wave of millennials and the last wave of Gen X. "The first time I heard ‘geriatric millennial’ I thought it was an oxymoron. Sarcastic, even. But as I thought more deeply about it, I realised how perfectly it describes so many of us," Dhawan writes. "Geriatric millennials are a special micro-generation born in the early 1980s that are comfortable with both analogue and digital forms of communication." Naturally, it's provoked a reaction on Twitter. Some people like it: Others have likened it to the term geriatric pregnancy, which can be used for mothers-to-be aged 35 and older: Others seem to be less charmed by the term: Geriatric millennials are far from the only cuspy micro-gen, or cuspers, as they are also known, a term which generally describes people born within three to five years of the beginning or end of a generation. Here are a few more to wrap your head around... <b>1. Zillennials</b> Perhaps unsurprisingly, the term zillennial bridges the Gen Z and millennial gap. Zillennials are born between 1993 and 1998, making them aged 22 to 28, so it's very possible that they have memories of using MSN Messenger, but may also have worn a bucket hat and made their fair share of TikTok dance videos in the last year. They could already be parents, but also might still live with their parents. <b>2. Xillennials</b> As well as having our geriatric millennials, people born at the beginning of the millennial generation, we also have xillennials, which more collectively describes the crossover between Generation X and millennials. The agreed date range of xillennials is roughly 1976 to 1982 – so there is a little crossover with geriatric millennials. <b>3. Generation Jones</b> Those on the cusp of Baby Boomers and Generation X are known as Generation Jones, a term coined by the cultural commentator Jonathan Pontell. Another name for the generation is Tweeners. According to Pontell, those born between 1954 and 1964 fall into the micro-gen. Right now, members of Generation Jones are aged 56 to 67. <b>Read more:</b>