To assess the perceived symptoms caused by the sinuses as defined by otolaryngology patients and clinicians. Multi-institutional cross-sectional study. Six academic outpatient otolaryngology practices. We performed a multi-institutional, cross-sectional study using a semantics-based questionnaire. Consecutive patients were enrolled at 6 academic otolaryngology centers from June 2020 to May 2021. The primary outcome examined patient and provider definitions for the symptoms caused by the sinuses from a list of 28 proposed terms covering 6 general categories. These data were also collected from otolaryngology faculty at the same institutions. Responses were obtained from 451 patients (54% female, mean age 48.3 years) and 29 otolaryngologists (38% female, mean age 37.4 years). Patients selected a median of 12 terms, compared to 8.5 for otolaryngologists. Among patients, the most frequently selected symptom domains were mucus (419, 92.9%), airflow (412, 91.4%), and pain (389, 86.3%). Compared to clinicians, patients more frequently selected symptoms related to the ear (difference, 48.3%; 95% confidence interval CI, 34.8%-59.3%), throat (difference, 35.7%, 95% CI, 22.0%-47.5%), systemic (difference, 34.4%, 95% CI, 21.2%-46.0%), mucus (difference, 20.5%, 95% CI, 10.2%-30.6%), and airflow domains (difference, 19.0%, 95% CI, 8.4%-29.3%). Multiple domains were selected by 98% of patients and 79% of providers. Semantic differences exist between patients and clinicians regarding the symptoms caused by the sinus with patients having a broader range of perceived symptoms. These differences may provide clues to improve communication between otolaryngologists and their patients.