A single BP reading of ANY figure is meaningless.
Blood pressure changes constantly, awake and asleep, and is affected by hundreds of things. Posture, illness, weight, activity, stress, age and medications are just a few.
One way to find out if blood pressure is raised to a level that could be considered 'high' is to wear a monitor at least 24hours. These usually record a BP every 30 minutes and the resulting data would be used as a tool with a view to treatment.
As for what constitutes a raised BP, well this also depends on hundreds of things.
wiflib