Is this a form of physical abuse?

I think it is. Maybe you don't see it that way because it feels normal to you. I don't know exactly what I'd do in this situation since they're your parents. I think maybe you should get into more clubs or get a job, whatever to stay out of that house as much as possible. I think this abuse will eventually build up, and start affecting you in ways you won't realize if this continues.

That is one hundred per cent genuine abuse and you should NOT put up with that. That is absolutely not okay and if this is a habit, you need to seek out an outside authority to put a stop to it. Preserve any evidence you can, stay out of the house, and if it keeps happening, call the police or social services or SOMETHING. That is dangerous behaviour and entirely unacceptable in a parental figure. The fact that you're flinching when people raise their hands/arms tell me this has already had some kind of effect on you even if its only subconscious. Bad bad bad.

That is what is called "beating the hell out of you" and is absolutely abuse. Tell someone about this as soon as is physically possible. Take pictures of any bruises and hide them for proof. You will need it.

Do not tolerate being hit. It is not normal child-rearing, it is not right by any stretch of the imagination. Do not let them hit you ever again. Do whatever is necessary to avoid a physical confrontation.

You see your parents as nice people,but!they are abuseing you.
I dont know if you want any other help her,but at least tell another adult this is happening.
You may need to tell them that you want them to stop abusing you,and that what ever it is that fires them up see if there is a way to fix that issue so they stop,thats if you can,if there is something at all you are doing and its driving them nuts and they dont know how to just talk to you..
As you needed to ask this question,tells me your a very young person,and if you keep having this problem with your parents you will grow up excepting this to be normal and also from others as well.And its not normal nor good.
Again! tell some one else (another adult,perhaps Aunt or something)others need to know this is happening and report it, if it gets worse.Unfortunalty bigger abuse starts from smaller like this.Not saying it will in your case,not to frighten you,but it happens that's for sure!
Take care,and dont be worried to stand up for yourself ok!

Yes. Straight up. There's no explanation. Just... Yes it is. Absolutely.

Okay. Despite the popular opinion here I think it should be laid out that a slap across the face is not physical abuse. I do not advocate slapping across the face or any form of corporal punishment for I feel it is negative for the psychological health of the child. Abuse is often found to be in a specific pattern and is normally excessive. If they are smacking you so hard than you drop the floor and are later searching for teeth, this now may cross a line to abuse. Also, for a website that is suppose to be caring and understanding, I find it ironic that nobody asked why you were slapped. Did you pour a glass of orange juice instead of milk? Or was it something such as being caught sneaking into your house at 2am and your parents were overwhelmed with fear? Do they slap you once a year or every day? There are a lot of variables at play here before one could consider this to be abuse. Once again, not the best choice of action of your parents part.

It doesnt matter why some one is being slapped there is no need fo rit.You dont understand the word abuse your self sorry!
Actualy this was mentioned "see if there is a way to fix that issue so they stop,thats if you can,if there is something at all you are doing and its driving them nuts" so It was asked why! but regardless it shoulnt happen!No excuses.
I can go on for ever,about what things like slapping can lead to ,but I want as I am not able to say to much here.
But let me tell you ASI that I have seen things that start just like this ,then end up far worse.I know as I right to a lady in prison for what she ended up doing as she was sick to death of what she had to put up with from a very young age and then the worse things it got to as a young adult,and it didnt start with abuse as you may think it is.