An order of magnitude was an approximate measure or system of classification of the amount of positive or negative digits found in a number on a base-ten scale.
While the USS Enterprise-D was investigating the Mar Oscura dark matter nebula in 2367, Data noted that "dark matter density is nearly one order of magnitude higher than in similar nebulae." (TNG: "In Theory")
When traversing the black cluster in 2368, the Enterprise-D encountered severe gravitational wavefronts that the shields were having difficulty protecting the ship front. After Geordi La Forge ran an addition five fusion reactors through the ship's shield array, theoretically doubling the shield strength, Worf observed that the "wavefront intensity has increased by an order of magnitude." (TNG: "Hero Worship")
In attempting to recreate the spatial trajector technology used by the Sikarians in order to get USS Voyager home in 2371, it was discovered that the natural trajector field created by Sikaris was "bigger than anything we've created by ten orders of magnitude." (VOY: "Prime Factors")