The definition of a yag is a synthetic garnet used as a gem and in lasers.
(noun)An example of a yag is a garnet made of aluminum and yttrium.
See YAG in Webster's New World College Dictionary
noun
See YAG in American Heritage Dictionary 4
noun
Origin:
Origin: y(ttrium)
Origin: + a(luminum)
Origin: + g(arnet)1
.Learn more about YAG