The quality or state of being attachable; the characteristic of being able to be attached or fastened.
From attachable + '-ness' (quality suffix), a standard English formation creating an abstract noun describing the property of being attachable.
This word is a perfect example of English's ability to build meaning: 'attach' (French) + 'able' (Latin) + 'ness' (Germanic) = one word combining three language families to describe whether something can be stuck to something else.
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