1. If a newspaper publishes more than once a day, is it publishing more than one issue, or more than one edition?
2. Technically, is a spider a bug or an insect?
3. What's the difference between sauce and gravy?
4. Is the vase you call "crystal" really crystal?
(1) An edition would be a newspaper issued at different times of the day or altered, as in a "morning edition" or a "foreign edition." The "bulldog edition" is a nickname given to the first edition of a newspaper placed on sale the night before. Newspapers rarely publish more than one printing of the same edition.
However, when we speak of a monthly magazine, we refer to the "January issue." The same holds true for a newspaper with a specific date - the Jan. 5 issue, for example. But on Sunday, it's always the Sunday edition.
(2) A bug. "Bug" loosely refers to any small creature with a lot of legs, and also to microorganisms. Insects have bodies divided into three parts with two pairs of wings and three pairs of legs. Bees and mosquitoes are insects. Spiders have four pairs of legs and are therefore technically not insects. They are arachnids.
(3) In the United States, gravy is the word for a soupy addition to meats, made from pan drippings. Sauce is prepared separately, not from drippings, and is used on vegetables, desserts, salads, etc. In Britain, however, gravy is called sauce.
(4) Not likely. Crystal is a clear, transparent mineral that looks like ice, and is usually a form of pure quartz. Glass is a hard, brittle, transparent substance made largely of silica. Fine glass, when etched, is often called crystal, but very rarely does it consist of natural crystallized quartz. If you buy a "crystal" vase, it more likely contains lead, and is called lead crystal.
SOURCES: Merriam-Webster's Synonyms; The Source: Random House Dictionary; The World Book Dictionary; 'The Dictionary of Confusable Words,' by Laurence Urdang.