What's the difference between "general" and "generic"?
General is the opposite of specific, whereas generic refers to something which has no unique features. To use the book example, a general geography book would be one without a particular focus on one area, while a generic geography book would be the same as every other book out there.
Sometimes they can be used interchangeably, but not always.
General
adjective
- of or pertaining to all persons or things belonging to a group or category: a general meeting of the employees.
- of, pertaining to, or true of such persons or things in the main, with possible exceptions; common to most; prevalent; usual: the general mood of the people.
- not limited to one class, field, product, service, etc.; miscellaneous: the general public; general science.
- considering or dealing with overall characteristics, universal aspects, or important elements, especially without considering all details or specific aspects: general instructions; a general description; a general resemblance one to another.
- not specific or definite: I could give them only a general idea of what was going on.
Generic
adjective Also, ge·ner·i·cal.
- of, applicable to, or referring to all the members of a genus, class, group, or kind; general.
- of, pertaining to, or noting a genus, especially in biology.
- (of a word) applicable or referring to both men and women: a generic pronoun.
- not protected by trademark registration: “Cola” and “shuttle” are generic terms.
General is the opposite of special. General and special refer to the applicability of a fact. For example, Einstein's General Theory of Relativity applies to all physical situations, but Einstein's Special Theory of Relativity applies only to situations in which everything involved is moving at constant velocity.
Generic is the opposite of specific. Generic and specific refer to the identification of a fact. Specific means a fact that has been specified. If you ask for (specify) a pain reliever, aspirin would be a specific pain reliever, while aspirin, acetaminophen, ibuprofen, and naproxen together would be generic pain relievers. If you ask for (specify) aspirin, Bayer would be a specific (brand), while all brands including store brands (as well as anything unbranded, if such exists) together would be generic aspirins.