Ramanujan's ternary quadratic form refers to a specific type of quadratic form that is expressed in three variables. One of the most notable forms studied by Srinivasa Ramanujan is given by the equation: \[ x^2 + y^2 + z^2 - xyz \] This particular form is significant in number theory and has connections to various mathematical problems, including partitions and representations of numbers as sums of squares.