The term 'alkaline' is used to describe a substance with a pH greater than 7.0. The five crossword solutions for this term are 'BASIC' (5 letters), 'BITTER' (6 letters), 'ACRID' (5 letters), 'SALTY' (5 letters), and 'CAUSTIC' (7 letters). BASIC refers to a substance that is neither acidic nor alkaline, while BITTER, ACRID, and SALTY all refer to tastes that can be associated with alkaline substances. Finally, CAUSTIC is an adjective used to describe a corrosive or destructive nature, which is often associated with alkaline substances.