What’s the difference between amiable and amicable? Their etymology is identical, but their senses are distinct.
Amiable means “agreeable,” “friendly,” suggesting a person or an experience marked by a congenial personality or atmosphere: “He seems like the amiable sort”; “They were engaged in an amiable conversation.” The word ultimately derives from amicus, the Latin word for “friend,” which is related to amare, meaning “love.” (The latter term is the basis of amatory and amorous, both of which refer to sexual feelings.)
Amicus itself was borrowed into English as a legal term; it is part of the phrase “amicus curiae” (sometimes shortened simply to amicus), which translates literally to “friend of the court” and refers to an individual or an organization that files an amicus brief or otherwise requests of a court the opportunity to weigh in about a legal issue.
Amicus also survives in the Spanish word amigo, which means “friend” and is sometimes used as such in American English.
Amicable means “peaceable, marked by goodwill, as in “We were relieved when we came to an amicable understanding about the issue.”