What is the number 1 perfect square?

I'm curious, can you clarify for me what exactly is the number 1 perfect square? I'm a bit fuzzy on the concept of perfect squares and how they relate to numbers, so a detailed explanation would be greatly appreciated. I'm specifically interested in understanding why the number 1 is considered the first perfect square, and how it fits into the broader context of perfect squares in general. Thanks in advance for your help!