IPA: /ɪˈdɛm.ətəs/
KK: /ɪˈdɛm.ə.təs/
Having swelling caused by an excess of fluid in the body's tissues.
The patient's legs were edematous, making it difficult for him to walk.
Edematous is formed from "edema" (from Greek "oidēma", meaning swelling) and the suffix "-ous" (meaning full of or characterized by). The word describes a condition characterized by swelling due to fluid accumulation.
Think of 'edema' which means swelling, and remember that 'edematous' refers to being full of swelling.