"a definite order" is correct and usable in written English.
You can use it to refer to a sequence or arrangement of things that is specific and established. Example Sentence: I need to complete my tasks in a definite order to ensure that my project is successful.
In most alphabets the characters are arranged in a definite order, or sequence (e.g., A, B, C, etc).
In the form of learning called chaining the subject is required to make a series of responses in a definite order.
Influenced by the works of Johann Gottlob Lehmann and Georg Christian Füchsel, Werner demonstrated that the rocks of the Earth are deposited in a definite order.
Calendar, any system for dividing time over extended periods, such as days, months, or years, and arranging such divisions in a definite order.
On April 5, 1797 (Old Style), Paul I changed the succession law, establishing a definite order of succession for members of the Romanov family.
Now that the Space Shuttle has become operational, its missions, taken one by one, seem random, but writer discovered since spending time at the Johnson Space Center, outside Houston, that there is a definite order and progression to the first dozen or so flights and those that will follow.
There's a definite pecking order to the annual jamboree of global leaders.
In a uniform grouping, dominance between various species is apparent in feeding competition, suggesting a definite nipping order.
There's a definite pecking order, with the short-wheelbase, enclosed-headlight models capable of bringing $10 million or more.
They were ranked in a definite genealogical order according to their relative seniority, and, in the course of filling the highest posts in his army and administration, the tsar had to consider not so much the candidate's personal merits as his genealogical seniority as defined by earlier precedents.
The concept is more easily defined when we work inside the boundaries of the valence bond theory (VBT) in which chemical bonds are established between pairs of atoms with a definite bond order (single, double, triple) for each bond.
