There are a total of 43 11-letter words containing 'hat', and the number may vary in different dictionaries. You can specify the dictionary and order.

• bisulphates ₂₁
• chatelaines ₁₈
• chatoyances ₂₂
• chatterbots ₁₉
• chitchatted ₂₂
• diphosphate ₂₂
• eschatology ₂₁
• hatchelling ₂₃
• hatchetfish ₂₃
• hatefulness ₁₉
• hatemongers ₁₉
• nonemphatic ₂₄
• phosphatase ₂₁
• phosphatide ₂₂
• phosphatize ₃₀
• rethatching ₂₁
• shatterable ₁₇
• washaterias ₁₆
• whatserface ₂₂
• whatsername ₂₀
• whatsisface ₂₂
• whatsisname ₂₀
• womanhaters ₂₀
• womanhating ₂₃
• dethatching ₂₁
• backchatted ₂₅
• chatterings ₁₇
• dendrachate ₁₈
• disulphates ₁₇
• hatchellers ₁₉
• hatchettite ₁₉
• hatlessness ₁₄
• mahatmaisms ₂₀
• mechatronic ₂₀
• persulphate ₁₈
• phosphating ₂₂
• phosphatise ₂₁
• sulphatases ₁₆
• sulphations ₁₆
• tetrarchate ₁₆
• unthatching ₂₀
• whatsomever ₂₂
• xanthations ₂₁

There are 43 11-letter words containing hat in the well-known word game dictionary, 13 in the Scrabble US (US/Canada/Thailand - TWL/NWL) dictionary, and 32 in the Scrabble UK (International - SOWPODS/CSW) dictionary, and 24 in the Words with Friends (WWF) dictionary.