The Lexico-Oxford Dictionary includes information on word origin.
Black's Medical Dictionary by Word. (Year of Publication). Title. URL
Example:
Merriam-Webster. (n.d.). Compassion. In Merriam-Webster.com dictionary. Retrieved January 4, 2020, from https://www.merriam-webster.com/dictionary/compassion
Cite in text as:
("Compassion," n.d.)
Note: Although the online dictionary lists the copyright date at the bottom of the website page, this changes each year and refers to copyright on the entire website. It is there for legal purposes and does not indicate when individual dictionary entries were published. It is for this reason that we use n.d. to represent no date.
