Someone who grew up primarily in the 1990s, or who has a fanatical attachment to that decade regardless of the fact they were born later. 90s kids and the "things they remember" are a popular subject for irritating Buzzfeed-esque pop culture lists extolling the virtues of that decade.

Someone stuck in the 90s. They have boyband hair and play pokemon on their gameboy and wear those combat trousers with tassly bits hanging off them, or perhaps a pink camo vest top.
They go on about No Doubt and the Spice Girls. They are quite lame and say things like "radical" and "wicked" in a non-scene kid way, with the occassional "for the win".

90s kid defines a person born around the mid 80s to the mid 90s. Part of being a 90s kid is living through the decade of change. The quality of cartoons. The lack of the Internet. The experience of the time in general that made them who they are today. It is not solely focused on what is remember in child hood, but how it shaped the views for a majority of the generation born within that time frame. 90s kids come in different forms, so you have those that are more egocentric, and those that are more open minded, but all in all, most 90s kids have a certain train of thought. Quality of life. Being taught by the generation before hand, they also have a sense of morals and views that have come into acceptance today, and many have been made possible because of them. Not to say they are the only contributing factors, but they have been a big part. They are not stuck in the past, but memories do male who you are.

A person who spent there entire childhood growing up in the 1990s decade. Generally those born in the 1980s are considered true 90s kids.

A 90's kid is someone who was a kid in the 90's. To determine what a 90's kid is, we have to define "90's" and "kid".

90's - Personally, I consider the 90's period to have been about late 1991 to 2001; if I had to put dates on it, it's July 1, 1991 (the midpoint of 1991) to September 10, 2001 (due to the tragic and massively changing events of the next day), however years as early as 1989 and as late as 2003 can be considered to have 90's influence.

Kid - Not a toddler or a teen; personally, I'd consider a kid age 4 - 12, inclusive, however the "kid" period could start as early as 2 or as late as 14 for some people.

What I would consider a 90's kid would be someone who spent a majority of their kid years in the 90's; ergo, born January 1, 1983 - March 10, 1993. The "perfectly 90's" kid, who spent the entirety of their kid years in the 90's would be born July 1, 1987 - September 11, 1988. However, due to personal experience, someone born outside this range could still be a 90's kid, and someone born inside this range could be an 80's or 00's kid. So if you're born in, say, 1981 or 1994 (or any time between the late 1970s and late 1990s) and consider yourself a 90's kid, have at it. There's also hybrids of two decades and all kinds of other stuff, it's not a hard line.

Sexy in a cool way. Only applies to those born from 1990 to 1999.

A distinct and frequently overlooked cultural micro-generation that exists between Gen-X and Millennial. Those who qualify were typically born between '78 and '84 and experienced most of their middle and high school years, or essentially 'came of age', during the 90's while being immersed in the youth culture of the time.