I usually write new words I learned or found on a website to help me remember them better. For example, I learned the word "holster" and I wrote "A holster is a thing used to cover a gun."
This is perfectly fine to me if there are 2 or 3 words per day. But the problem is I learn about 10 - 15 new words a day and it looks strange to use the word "thing" over and over again.
I want to know alternative words for the word "thing."
After I read several answers to this question. It sounds like I can say "A holster is used to cover a gun." If so, is this sentence sounds better than "A holster is a thing used to cover a gun"?