terra incognita/inkogʹneetə, inʹkognitə/ noun (pl terrae incognitae /ˌteree inkogʹneetee, inʹkognitee/)

• back number
• back of beyond
• back off
• back out
• backpack
• back passage
• backpedal
• back projection
• back room
• backroom
• back room boys
• back row
• backscattering
• backscratch
• backscratching
• back seat
• back-seat driver
• back shift
• backside
• backsight
• back slang
• backslapping
• backslash
• backslide
• backspace