Alone
Solitude, Single
noun, の adjective
The kanji and the word are exactly the same. That means they share meanings as well.
While 一人 simply means "one person," 独り carries a stronger sense of being alone, often with connotations of solitude. It can also mean someone is single (as in not married).
The reading is different from the one you learned (this is kun'yomi). There's an easy way to remember it, though. 一人 and 独り share the same readings and mean almost the same thing. Just try to remember that this ひとり is used to emphasize solitude.
全てを失って、独りぼっちになってしまった。
After losing everything, I ended up all alone.
これからずっと独りで生きなくちゃいけないのか。
It seems like I have to live alone from now on.
彼も独りで住んでいるよ。
He lives alone too.