All chickens are birds but not all birds are chickens?

There must be some word that describes that statement but i can't for the life of me work out what it is and its really bugging me.
Other examples:
All squares are rectangles but not all rectangles are squares.
All iPhones are touch phones but not all touch phones are iPhones.
I could go on, but im really keen to know what it is.

Added (1). River, I think you mean causal nexus, not casual. But i mean everyone makes spelling mistakes. Its better than the other answers, but im not sure that causal nexus is actually the term that you would use to describe this phenomena.

I put my iphone in the washer?

I accidentally scooped up my iphone 5 with my sheets. It was in the washer, with hot water, for 20 minutes. I pulled it out immediately after I'd noticed it was gone. It's been in a closed bag of rice for about 3 hours so far. How long should I keep it in there?

Is it past being able to be saved? Should I just buy a new one? I'm not really sure if I should go out and buy a new one if a new iphone is coming out soon. Does anyone know?

Thank you! I'm so dumb lol

Installing iOS7 beta instalment?

Basically i was trying to put the ios7 firmware on my iPhone 5 without restoring it and it said "the firmware is not available" so I was wondering if its just because it wasn't restored or whether it just won't work

Should I buy an iPhone 5? Or save my money?

Well I currently have a Galaxy S3 & I'm not much of an android user. I've always wanted an iPhone which I've never had. Should I buy an iPhone 5? Or save my money for something's else? Please give me reasonable opinions (: thank you!

Why does amazon take so long to ship stuff?

I ordered a simple, clear, plastic iPhone 4S case on June 9, 2013. When I ordered it, I selected standard shipping (3-5 business days). My delivery estimate is now July 3-July 23! That's insane! Why does it take so long; it's just an iPhone case?

Buying an iPhone 5 from Best Buy?

I want to buy an iPhone 5 from Best Buy because they are selling them for $150, $50 less than at a Verizon store. My contract isn't up until March 2014. I have a basic phone right now and hate it. My dad is letting me use his upgrade though (he rarely uses his phone). I know I would be able to use his upgrade at an actual Verizon store, but would I be able to use his upgrade at Best Buy?

Most protective case for iPhone 4?

I dont care how bulky it is, but I want a very protective case that will protect my phone if I drop it cuz i am very clumsy. I would prefer under $80. I already have a Lifeproof and it is not lifeproof! It cracked so what other cases r there?