> "acquire" just meant "a load cannot be reordered before this barrier"

I'm pretty sure its "loads / stores cannot be reordered before this barrier". And technically, its "load-acquire", because the load-acquire is what the ordering is relative against. The C++ model does not match assembly-language of various architectures (though ARM64 was designed with C++11's memory model in mind)

Ditto with store-release. "loads/stores cannot be reordered past the store-release".

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    // Writing to protectedValue1 must occur after the lock.
    lock(); // load-acquire is part of all locks
    protectedValue1 = foobar();
    localVariable = protectedValue2;
    unlock(); // store-release is part of all unlocks
    // Reading protectedValue2 must occur before the store-release. If the protectedValue2 read occurs here, then some other thread may modify it.

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Citation: LDAR and STLR from ARM64, which applies to "any memory access".