compund x is known to absorb at 510nm. If you dilute a solution containing x by 1/4, by how much does the absorbance increase or decrease. if it stays the same just state it stays the same.why

What does diluting by 1/4 mean? If we dilute from 100 to 400 that is 4 times; if we change 100 to 25 it is MORE concentrated (not less). I don't know what 1/4 means.