What are strong and weak acids? How do they differ from diluted and concentrated acids?

Acid strength relates to the degree of ionisation in aqueous solution. A strong acid is completely ionised in aqueous solution. A weak acid is only partially ionised in aqueous solution.On the other hand, acid concentration relates to the amount of substance. A diluted acid is an acid dissolved in large amounts of water, whilst a concentrated acid is an acid dissolved in small amounts of water.