What do guys mean when they call girls hot?

when a guy says a girls hot, what does he mean? so a situation ive beens in. I changed alot over the summer. im a 13 btw. and i died my hair darker with a new cut and changed my style. a bit of a punkish look. but not overboard. and im kinda preppy. and this guy that a i like alot told one of my other guy friends something like this "Dude did you see Cara this summer? She changed her hair and shes got an *** now! Shes hot!" haha it made me laugh a lil bit when he told me. i just kinda wanna know what he meant or what his intenions are by saying that stuff. ive been called hot by other guys too. but this just i used as an example. btw. i know what hot means so dont call me stupid or say stufff like "wtf what do you think it means?" i got stuff like that before. just i want opinions. thanks.