1. (cosmology) one billion (10^9) years
   "the universe is approximately 14 gigayears old"

Encyclopedia: Gigayear

• lyophilization
• lyophilize
• lyophilized
• lypressin
• Lyra
• lyrate
• lyrate leaf
• lyre
• lyre snake
• lyre-shaped
• lyrebird
• lyreflower
• lyric
• lyric poem
• lyrical
• lyricality
• lyrically
• lyricism
• lyricist
• lyrist
• Lyrurus
• Lyrurus mlokosiewiczi
• Lyrurus tetrix
• Lysander
• lyse