The hamlets of Avinières, Val-Martin, La Tuilerie-Bignon were the responsibility of numerous lords, as well as of the Dames de Poissy and the Vaux-de-Cernay Abbey.

Some historic structures in the village suffered irreparable damage from a freak storm with tornado strength winds that struck France in December 1999.

In 1954, Mr. Ortet, owner of the "Ferme de le Tuilerie", asked a real estate agent, Daniel Feau, to find a potential buyer for his property.

With Dominique Motte, he suggested the creation of a new "champion-trophy" to Pierre Menet, the chairman of the Lancôme Company, whose goal would be to bring together eight of the best players in the world.

By incrementally and regularly gaining plots of land, the cistercian monks turned the agricultural estate into what was then considered to be a model farm, setting well distributed buildings around a farmyard.

The coat of arms of Saint-Nom shows in its center the "fasce bretessée" which evokes the etymology of Bretèche (from the Latin bretachiae): a fortification built at the entrance of a forest.

The three five-petalled leaves of the Potentilla reptans (quintefeuilles [fr]) symbolize the Forest of Marly-le-Roi, a large part of which belongs to Saint-Nom.

The fork-tailed lion comes from the seal of Amaury de Montfort, shown on historical charts dating back to 1226 and leased to the Monks of Saint-Nom.