esophageal veins vs oesophageal veins

esophageal veins and oesophageal veins both are nouns.

Word	Noun	Adjective	Verb	Adverb
esophageal veins	Yes	No	No	No
oesophageal veins	Yes	No	No	No

As nouns, esophageal veins and oesophageal veins are synonyms defined as:

esophageal veins and oesophageal veins: small veins from the esophagus emptying into the brachiocephalic vein or the azygos veins

Other synonyms of esophageal veins include venae esophageae.

esophageal veins (noun)	oesophageal veins (noun)
small veins from the esophagus emptying into the brachiocephalic vein or the azygos veins	small veins from the esophagus emptying into the brachiocephalic vein or the azygos veins