Y Y /ˈwaɪ/

noun

1. The 25th letter of the Roman alphabet  ( wye , Y )
   the 25th letter of the Roman alphabet
   
2. A silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys  ( atomic number 39 , Y , yttrium )
   a silvery metallic element that is common in rare-earth minerals; used in magnesium and aluminum alloys