[{"Bold_text": "noun", "List Items": ["a group or set of four persons or things.", "Bookbinding.four gathered sheets folded in two for binding together.", "Mathematics.an expression of the forma+bi+cj+dk,wherea,b,c,anddare real numbers;i2=j2=k2= ?1; andij = ?ji = k, jk = ?kj = i,andki = ?ik = j.a quantity or operator expressed as the sum of a real number and three complex numbers, equivalent to the quotient of two vectors. The field of quaternions is not commutative under multiplication.", "an expression of the forma+bi+cj+dk,wherea,b,c,anddare real numbers;i2=j2=k2= ?1; andij = ?ji = k, jk = ?kj = i,andki = ?ik = j.", "a quantity or operator expressed as the sum of a real number and three complex numbers, equivalent to the quotient of two vectors. The field of quaternions is not commutative under multiplication."]}]