order, in the order of, of the order of, on the order of

The phrases of the order of, on the order of and in the order of are wordy substitutes for approximately or about, and should be used sparingly.

• Police are searching for an object with a length in (not of the order of) centimetres, not metres.
• The speed of the aircraft was about (not on the order of) 600 km/h when the alarm sounded.
• Clients should have approximately (not something in the order of) $10 000 to open an investment account.