from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The highest degree of quality or purity in diamonds or pearls.
- n. The foremost rank or quality: a pianist of the first water.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The highest quality of gemstones, especially of diamonds and pearls.
- n. Of the highest rank or quality.
from the GNU version of the Collaborative International Dictionary of English
- adj. the highest quality or purest luster; -- said of gems, especially of diamond and pearls.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the highest quality gems
Probably translation of Arabic mā', water, water luster.(American Heritage® Dictionary of the English Language, Fourth Edition)
first + water (Wiktionary)