• thoreies,
• thirities,
• theiries,
• thirtee,
• thirtey,
• thiries,
• thirtie,
• thirites,
• thirtes,
• thirtith,
• thirten,
• athirtis,
• thievies,
• thories,
• thires,
• thirtys,
• throies,
• therpies,
• thrities,
• thirdies

• threads,
• thirty-six,
• thwartwise.

The adjective form of the word "thirties" is "thirtieth".

The plural of the "thirties" can be the "thirties".

The singular of the "thirties" can be the "thirty".