<synset id="n13824929" type="n">
<lex_filenum>24<lex_filenum/>
<word lex_id="0">refractive index<word/>
<word lex_id="0">index of refraction<word/>
<pointer refs="n13819207">Hypernym<pointer/>
<def>the ratio of the velocity of light in a vacuum to that in a medium<def/>
<synset/>