==Definition==For a small body with semimajor axis formula_1, eccentricity formula_2, and inclination formula_3, relative to the orbit of a perturbing larger body with semimajor axis formula_4, the parameter is defined as follows::formula_5The quasi-conservation of Tisserand's parameter is a consequence of Tisserand's relation.
"New RHS Dictionary of Gardening" 4: 676.