An acidic solution is any type of solution that has an excess of hydrogen ions, or protons. The word "acidic" comes from the Latin word "acidus," which means sour and sharp.
A solution can be more or less acidic depending on the number of protons present in the solution. Strongly acidic solutions have a pH between 0 and 4 and have a high proton content. Strong acids completely dissociate in water into their respective ions. Weak acids have fewer protons in them than strong acids and partially dissociate in water. Weakly acidic solutions have pH values between 3 and 7.