Usually people say that family is the people who live with you. But that doesn't mean nobody outside your house can be a part of your family. The people in your family are the people who you are a bout a great deal and who cares about you. Often these people life with you or are related to you but that doesn't mean its always the case. Your family can be your mom, dad, sibling and all your other relatives but not all families look like these. Some families have only one child or only one parent, other families can have two dads or two moms, some children are adopted and they may not look like them at all, but they are still a family.
Other families may not be related at all but be a group of friends that take care of each other. There are so many different types of families and no two families are exactly the same. Each and every family is special no matter what they look like or how they are related. Families come in different shapes, colors, and sizes, just like people and the word "family" can mean a whole lot of different things to different people.
So personally, for me family is simply the ones who will truly accept you even if you do things that are dumb and/or the biggest regrets or mistakes in your life. They will always be the one who will never ever leave you alone in your darkest times and they are the ones who will always be the one who will have your back no matter what happens. Family means to care for each other, to love someone unconditionally, to support each other and to also love their flaws and help them in each and every step of the way.
Always remember we all have different definition of family but if we sum up all of our ideas I'm sure we will all have the same answer.