say it: WIL-is
willis is a noun meaning "English physician who was a pioneer in the study of the brain (1621-1675)". It carries one recorded sense.
English physician who was a pioneer in the study of the brain (1621-1675)
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for willis come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.