Etymology From Middle English affection, affeccion, affeccioun, from Old French affection, from Latin affectiōnem, from affectiō; equivalent to affect + -ion.
1
The act of affecting or acting upon.
2
The state of being affected, especially: a change in, or alteration of, the emotional state of a person or other animal, caused by a subjective affect (a subjective feeling or emotion), which arises in response to a stimulus which may result from either thought or perception.
3
An attribute; a quality or property; a condition.
A Porism is a proposition in which it is proposed to demonstrate that some one thing, or more things than one, are given, to which, as also to each of innumerable other things, not given indeed, but which have the same relation to those which are given, it is to be shewn that there belongs some common affection described in the proposition.1756, Robert Simson, Euclid's Elements:
4
An emotion; a feeling or natural impulse acting upon and swaying the mind.
Our affections for wild animals are distributed very unevenly. Take insects.2013 August 23, Mark Cocker, “Wings of Desire”, in The Guardian Weekly, volume 189, number 11, page 26:
It is known that each individual has a variety of affections, one affection when in joy, another when in grief, another when in sympathy and compassion, another when in sincerity and truth, another when in love and charity, another when in zeal or in anger, another when in simulation and deceit, another when in quest of honor and glory, and so on.1905, Emanuel Swedenborg, chapter 27, in John C. Ager, transl., Heaven and Hell:
5
A feeling of love or strong attachment; a feeling of enjoyable and comforting fondness.
I have a lot of affection for my little sister.
The marriage therapist suggested they show each other more affection.
4 more examples
Mr. Bennet missed his second daughter exceedingly; his affection for her drew him oftener from home than anything else could do. He delighted in going to Pemberley, especially when he was least expected.1813 January 27, [Jane Austen], chapter 61, in Pride and Prejudice: […], volume (please specify |volume=I to III), London: […] [George Sidney] for T[homas] Egerton, […], →OCLC:
What is more, they are protected from even such discomfort as the dislike of his prisoners may cause to a gaoler by the hypnotism of the convention that the natural relation between husband and wife and parent and child is one of intense affection, and that to feel any other sentiment towards a member of one's family is to be a monster.1908, George Bernard Shaw, Getting Married: Spurious "Natural" Affection:
"Did you ever like me back, Ryan? All those years, I didn't know how to show my affection for you, so I wasn't sure if you weren't getting it or you just didn't care. But I need to know which it was."2016 March 8, Jocelyn Samara D., Rain (webcomic), Comic 806 - Terrible Excuse:
Dated a girl that I hate, for the attention / She only made it two days, what a connection / It's like you'd do anything, for my affection / You're going all about it in the worst ways2021 August 13, Gayle, Sara Davis, David Pittenger, “abcdefu”, in A Study of the Human Experience Volume One, performed by Gayle:
6
Medicine, SciencesArchaic A disease; a morbid symptom; a malady.
a pulmonary affection1834, Samuel George Morton, Illustrations of Pulmonary Consumption:
The recedent or retrograde form is marked by a sudden subsidence of the inflammatory state of the joints, succeeded immediately by an affection of some internal part, where is thenceforth the seat of the morbid manifestations.1851, Russell Thacher Trall, The Hydropathic Encyclopedia, page 123:
1 more example
A heavy clay soil is bad for all neuralgics, and the house should be dry, and on a sandy or gravel soil. The desideratum for all neuralgic affections is perpetual summer […]1907, The Medical Brief, volume 35, page 840:
Etymology From Middle English affection, affeccion, affeccioun, from Old French affection, from Latin affectiōnem, from affectiō; equivalent to affect + -ion.
Why, truth is truth, I do not think my lady Isabella ever much affectioned my young lord, your son: yet he was a sweet youth as one should see.1764, Horace Walpole, The Castle of Otranto, section V: