1. The number that is represented as a one followed by 18 zeros
   - trillion [Brit, archaic]

Type of: large integer

• hydrogen bond
• hydrogen bromide
• hydrogen carbonate
• hydrogen chloride
• hydrogen cyanide
• hydrogen fluoride
• hydrogen iodide
• hydrogen ion
• hydrogen ion concentration
• hydrogen peroxide
• hydrogen sulfide
• hydrogen sulphide
• hydrogen-bomb
• hydrogenate
• hydrogenation
• hydrogenise
• hydrogenize
• hydrogenous
• hydrographer
• hydrographic
• hydrographical
• hydrography
• hydroid
• hydroiodic acid
• hydrokinetic