There are a total of 24 11-letter words containing 'vac', and the number may vary in different dictionaries. You can specify the dictionary and order.

• evacuations ₂₀
• evacuatives ₂₃
• medevacking ₂₉
• medivacking ₂₉
• novaculites ₂₁
• revaccinate ₂₂
• ultravacuum ₂₅
• vacationers ₁₉
• vacationing ₂₂
• vacationist ₁₉
• vaccinating ₂₅
• vaccination ₂₃
• vaccinators ₂₂
• vaccinology ₂₇
• vacillating ₂₃
• vacillation ₂₁
• vacillators ₂₀
• vacuolation ₂₁
• vacuousness ₂₁
• vivaciously ₂₆
• bupivacaine ₂₀
• vaccinatory ₂₁
• vacillatory ₁₉
• vivacissimo ₂₁

There are 24 11-letter words containing vac in the well-known word game dictionary, 18 in the Scrabble US (US/Canada/Thailand - TWL/NWL) dictionary, and 22 in the Scrabble UK (International - SOWPODS/CSW) dictionary, and 20 in the Words with Friends (WWF) dictionary.