To have an abundance of something is to have more than you need. It's often used to describe positive qualities, such as "an abundance of love."
Abundance is the opposite of scarcity. An abundance of wealth is a ton of cash. An abundance of friends sounds like a good thing, but it can get overwhelming when it comes to scheduling time to hang out or buying gifts. This noun comes from to us from the mid-14th century French, via the Latin abundantia, meaning "fullness, plenty."