What’s the difference between hiking, backpacking, thru-hiking, and trekking?

Hi! I’m trying to understand how these terms are actually used in everyday American English:

What’s the difference between hiking, backpacking, thru-hiking, and trekking?

• When do you use each word?
• Do Americans actually use “trekking,” or does it sound unnatural?
• Would you ever say something like “going hiking for a week,” or would that usually be “backpacking”?
• How would you describe a multi-day trip on a trail (like part of the Appalachian Trail or John Muir Trail)?

I’ve seen definitions online, but I’m more interested in how people really talk in the US.

Thanks!