An alkaline earth metal is a group of elements in the periodic table that includes beryllium, magnesium, calcium, strontium, barium, and radium. The three crossword solutions for this term are LYE (3 letters), ERBIUM (6 letters), and BASE (4 letters). LYE is an alkaline solution made from ashes, which is used in soap-making and other processes. ERBIUM is a rare earth element with atomic number 68, and BASE is a substance that has a pH greater than 7.