Odor is a smell perceived by a person. It is an observation that can help an investigation, but it is not a precise identification of a substance.
What this means at your property
An odor that changes with HVAC operation, rainfall or room use may provide useful timing information. Fragrance can alter perception without correcting the source. Some harmful conditions may have no reliable warning odor.
What should I record before an assessment?
Note the location, timing, duration and recent events such as leaks or new materials. Describe the smell in ordinary terms and ask how the source will be investigated rather than assuming one treatment fits every odor.