When alcohols dissolve in water they also dissolve molecularly and do not ionize. Since no OH - ions are released, alcohols are not bases. Furthermore, if nuclear protons were transferred, then elements would change their identities in acid-base reactions, since the atomic numbers of the atoms involved would be altered. Strength and concentration mean the same thing. These two terms are often confused by students.
Strength refers to the percent of molecules that ionize and form ions in solution.
It is interesting to note that the percent of acid molecules that normally ionize in a weak acid actually increases as the acid concentration is decreased through dilution with water. Thus, acetic acid actually becomes slightly stronger as the solution is diluted.