What is left behind when a Bronsted and Lowry acid gives up its proton?

1. An acid is defined by the fact that it can hand over a proton. 2. What remains once the proton has gone is called the conjugate base of that acid. 3. It counts as a base because it can take the proton back and re-form the acid. 4. A conjugate acid is what forms when a base gains a proton, which is the mirror case. _Source: OpenStax Chemistry (CC BY 4.0), Ch 14 "Acid-Base Equilibria", section 14.1 Brønsted-Lowry Acids and Bases_