1. Upon that or this; in consequence of that; immediately.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• thereason,
• whereapon,
• rhereupon,
• fhereupon,
• 6hereupon,
• 5hereupon,
• tgereupon,
• tbereupon,
• tnereupon,
• tjereupon,
• tuereupon,
• tyereupon,
• thwreupon,
• thsreupon,
• thdreupon,
• thrreupon,
• therupon,
• Therupen,
• Theruppon,
• Thirupon

• threepenny,
• threepence.

The adjective form of "thereupon" is "thereupon".

The plural form of the word "thereupon" is "thereupons".

The singular form of the word "thereupon" is "thereupon".