There are a total of 147 8-letter words containing 'back', and the number may vary in different dictionaries. You can specify the dictionary and order.

• backache ₂₃
• backbars ₂₁
• backbeat ₂₁
• backbend ₂₃
• backbite ₂₁
• backbone ₂₂
• backcast ₂₁
• backchat ₂₃
• backcomb ₂₇
• backdate ₁₉
• backdoor ₁₉
• backdown ₂₃
• backdrop ₂₂
• backends ₂₀
• backfill ₂₃
• backfire ₂₁
• backfist ₂₁
• backfits ₂₁
• backflip ₂₅
• backflow ₂₅
• backhand ₂₂
• backhaul ₂₂
• backheel ₂₁
• backhoes ₂₀
• backings ₂₁
• backland ₂₁
• backlash ₂₁
• backless ₁₉
• backlift ₂₂
• backline ₂₀
• backlink ₂₄
• backlist ₁₉
• backload ₂₀
• backlogs ₂₁
• backlots ₁₉
• backmost ₂₁
• backouts ₁₉
• backpack ₂₈
• backpass ₂₁
• backrest ₁₈
• backroom ₂₁
• backrows ₂₁
• backrush ₂₁
• backsaws ₂₁
• backseat ₁₈
• backsets ₁₈
• backside ₁₉
• backslap ₂₂
• backslid ₂₀
• backspin ₂₂
• backstab ₂₁
• backstay ₂₀
• backstop ₂₁
• backtalk ₂₃
• backveld ₂₄
• backward ₂₂
• backwash ₂₃
• backwind ₂₃
• backwood ₂₂
• backwrap ₂₄
• backyard ₂₁
• bareback ₂₁
• blowback ₂₅
• blueback ₂₃
• buybacks ₂₄
• callback ₂₃
• cashback ₂₃
• clapback ₂₅
• clawback ₂₅
• comeback ₂₄
• cutbacks ₂₂
• diebacks ₁₉
• drawback ₂₂
• fallback ₂₃
• fastback ₂₁
• fatbacks ₂₁
• feedback ₂₂
• finbacks ₂₂
• fireback ₂₁
• fullback ₂₄
• giveback ₂₄
• grayback ₂₂
• halfback ₂₄
• hardback ₂₁
• hogbacks ₂₂
• holdback ₂₂
• humpback ₂₇
• keelback ₂₃
• kickback ₂₉
• laidback ₂₀
• mossback ₂₁
• outbacks ₁₉
• paybacks ₂₃
• pingback ₂₄
• playback ₂₄
• plowback ₂₅
• puffback ₂₈
• pullback ₂₄
• pushback ₂₄
• redbacks ₁₉
• rollback ₂₀
• roorback ₁₈
• rowbacks ₂₁
• runbacks ₂₀
• scatback ₂₁
• setbacks ₁₈
• skewback ₂₅
• slotback ₁₉
• snapback ₂₂
• softback ₂₁
• sowbacks ₂₁
• swayback ₂₃
• tailback ₁₉
• talkback ₂₃
• tiebacks ₁₈
• tombacks ₂₁
• turnback ₂₀
• unbacked ₂₁
• wingback ₂₄
• zwieback ₃₀
• backfats ₁₉
• backhoed ₂₀
• haulback ₁₉
• seatback ₁₆
• wetbacks ₁₉
• backband ₁₉
• backbond ₁₉
• backburn ₁₈
• backfall ₁₉
• backfile ₁₉
• backpays ₂₁
• backseys ₁₉
• backwall ₁₉
• backword ₂₀
• backwork ₂₃
• flatback ₁₉
• flybacks ₂₂
• foldback ₂₀
• greyback ₂₀
• howlback ₂₂
• laybacks ₁₉
• liftback ₁₉
• loanback ₁₆
• pickback ₂₄
• rebacked ₁₇
• slowback ₁₉
• waybacks ₂₂

There are 147 8-letter words containing back in the well-known word game dictionary, 109 in the Scrabble US (US/Canada/Thailand - TWL/NWL) dictionary, and 128 in the Scrabble UK (International - SOWPODS/CSW) dictionary, and 120 in the Words with Friends (WWF) dictionary.