Emily Dickinson Lexicon

AC'ID, n.

A compound capable of uniting with salifiable bases and thereby forming salts. An acid may be composed either of a simple or compound acidifiable base united with one or more acidifying principles. Those acids which were first recognized were sour to the taste (hence the name) and capable of reddening blue vegetable colors. Many acids are now known which have neither of these properties. An acid is always the electro-negative ingredient of a salt.