decubitus ulcer vs pressure sore

decubitus ulcer and pressure sore both are nouns.

Word	Noun	Adjective	Verb	Adverb
decubitus ulcer	Yes	No	No	No
pressure sore	Yes	No	No	No

As nouns, decubitus ulcer and pressure sore are synonyms defined as:

decubitus ulcer and pressure sore: a chronic ulcer of the skin caused by prolonged pressure on it (as in bedridden patients)

Other synonyms of decubitus ulcer include bedsore.

decubitus ulcer (noun)	pressure sore (noun)
a chronic ulcer of the skin caused by prolonged pressure on it (as in bedridden patients)	a chronic ulcer of the skin caused by prolonged pressure on it (as in bedridden patients)