The phrase "a significant order for" is correct and usable in written English.
It can be used when referring to a large or important request for goods or services, typically in a business or commercial context.
Example: "The company received a significant order for 10,000 units of their latest product, which will boost their production schedule."
Alternatives: "a substantial order for" or "a major order for".
The deal is the first significant order for a large-scale fuel cell that generates power by combining with oxygen rather than with hydrogen.
Any significant order for American troops to step back in would undermine the credibility of the Iraqi government and be a visible setback for the training program, risking the entire United States strategy.
BMW reports: Rolls-Royce continues to see strong customer demand for Wraith, significant orders for the recently announced Ghost Series II and good demand for the Phantom family of cars across the world.
Rolls-Royce saw strong demand for its Wraith models, and said it had "significant orders" for its Ghost Series II, which is due out in autumn this year.
Those orders come on top of an already significant order book for Airbus's standard A320 planes, bringing the company's total single-aisle-plane backlog to well over 3,000.
The only significant order of business for 1796 was getting through Congress a treaty with England.
Elderly patients did not have a significant different ranking order for the preference statements than the other three age groups (r = 0.0193; p = 0.41).
A mixed linear model with 'type of playback sound', 'oestrus state' and 'presentation order' as fixed factors and subject as a random factor revealed a significant difference for presentation order (F1,46 = 7.2, p = 0.01) and a significant interaction between the type of playback sound and presentation order (F2,46 = 3.9, p = 0.027).
It said: A number of significant orders which had been expected and planned for production in the second half of the current financial year have continued to be delayed.
EADS said Airbus, which generates more than two-thirds of the group's revenue and 58percentt of operating profit, continues to have a significant backlog of orders for commercial aircraft, which should help to keep money flowing to the company in the near term.
