Definitions of Se:

• noun:   a toxic nonmetallic element related to sulfur and tellurium; occurs in several allotropic forms; a stable gray metallike allotrope conducts electricity better in the light than in the dark and is used in photocells; occurs in sulfide ores (as pyrite)
• noun:   the compass point midway between south and east; at 135 degrees
• name:  A surname (very rare: popularity rank in the U.S.: #42159)