conundrum conundrum /kəˈnʌndrəm/

noun

1. A difficult problem  ( brain-teaser , conundrum , enigma , riddle )
   a difficult problem
   
   

 mason's level mason's level /ˈmeɪsənz ˈlɛvəl/

noun

1. A level longer than a carpenter's level  ( mason's level )
   a level longer than a carpenter's level
    The mason used his level to ensure the bricks were perfectly aligned.
   The mason used his level to ensure the bricks were perfectly aligned.
   
   

 tribade tribade /ˈtraɪbeɪd/

noun

1. A female homosexual  ( gay woman , lesbian , tribade , les [Informal] , lez [Informal] )
   a female homosexual
   
   

 reversible reversible /riːˈvɝːsəbəl/

adjective

1. () Capable of reversing or being reversed  ( reversible )
   capable of reversing or being reversed
    Reversible hypertension
   reversible hypertension
   
2. (physics) capable of assuming or producing either of two states  ( reversible )
   (physics) capable of assuming or producing either of two states
    A reversible chemical reaction
   a reversible chemical reaction
    A reversible cell
   a reversible cell
   
3. Capable of being reversed or used with either side out  ( reversible , two-sided )
   capable of being reversed or used with either side out
    A reversible jacket
   a reversible jacket
   
4. Capable of being reversed  ( reversible )
   capable of being reversed
    A reversible decision is one that can be appealed or vacated
   a reversible decision is one that can be appealed or vacated
   

noun

1. A garment (especially a coat) that can be worn inside out (with either side of the cloth showing)  ( reversible )
   a garment (especially a coat) that can be worn inside out (with either side of the cloth showing)
    Her reversible jacket was red on one side and black on the other.
   Her reversible jacket was red on one side and black on the other.