The phrase "are generally defined by" is correct and usable in written English.
You can use it when explaining how certain concepts, terms, or categories are typically characterized or described.
Example: "In the field of biology, species are generally defined by their genetic makeup and reproductive isolation from other groups."
Alternatives: "are typically characterized by" or "are usually described by".
Microprocessors are generally defined by the number of pieces of information they can manipulate at once.
Football Outsiders found that this proved true in the N.F.L.: "championship teams are generally defined by their ability to easily win games over inferior teams".
Even now, parts for women are generally defined by their relationship to their male lead and as a result, anyone willing to construct a movie without one is better equipped to find new material.
The electron pre-acceleration and/or heating are generally defined by the small-scale plasma condition.
Programs are generally defined by the frequency of product introductions and level of product improvement with each new release.
Scientific workflows are generally defined by four entities: abstract workflow, concrete workflow, workflow configuration and workflow engine.
As a brief background, a stem cell is generally defined by its capacity for extensive self-renewal and ability to generate terminal progeny.
In the early days of the republic, when regional disputes were the foremost conflict of the era, nominees were generally defined by their home turfs.
White noise is generally defined by hazy and inharmonious hissing — it's noise-eating noise, anti-noise, a way of drowning out other sounds.
And a moundsman's prowess is generally defined by clear and objective terms (a win-loss record, earned-run average, the number of strikeouts or walks administered).
Then we back to a bit more standard panel fare, with Hoberman repeating the line that your approach to mistakes is generally defined by how many you can afford to make.
