What is the difference between a legend or a key? Is it still called a legend if it is located at the top, rather than the bottom of results?
"Legend" implies that its entries are generics, as with terrain types on a map, while "key" implies that its entries are specific, as with one symbol designating the Museum of Natural History, another the Metropolitan Museum of Art, etc. Generally, nobody is going to get real mad no matter which you use. It doesn't matter where they're located.
A "Caption" used to be a box you put at the top of a map, hence the "Cap" part.
The "Legend" is the explanatory information within a Caption that allows you to understand how to use the map, especially the Keys. It is a syllogistic synopsis, a short story if you will.
The "Keys" are the symbols and numbers within the Caption that the Legend explains.
Somehow the two got mixed up over the centuries.
Imagine if you had a Caption with Keys but no Legend to explain what they mean. These types of maps are actually all too common. They are fun and challenging but sometimes impossible to understand because you have to be a bit of a cryptologist to decipher what the symbols mean sometimes. We've all seen the dotted line which represents a trail, a straight line a road, a wavy line a river, a circle with a triangle in it a campground, a skull and bones something dangerous etc.
Now imagine if you had a Caption with a Legend but no symbols. These maps exist too, as the explanation could be about shaded areas on the map with no need for designating symbols.
Somehow the Legend came to be called the "Key", which is bizarre, as if the map had a single symbol. Just as odd, some Captions are called the "Compass" which is actually the Rose Compass, which is a diagram explaining the cardinal directions relevant to the map.
4First off, welcome to English.se. It'd be helpful to see this substantiated. Can you source this answer in some way?– virmaiorMar 11, 2014 at 2:41
Sounds familiar, mb what I learnt in Waldorf school as a kid. A legend defines generic/diffuse map features/zones not specific places: striped/colored areas, could be forests, regions of control, and lines/dots/dashes could be roads, rivers, paths taken by famous people; keys are nameable, geographically centered places/features that don't represent well as areas or straight/curved lines: stars for capitals, circles of different sizes for cities of relative size, waterfall symbols, a tree symbol for a Named Tree of interest, a house that's a historic landmark... Jan 26 at 7:46
A legend is a caption, a title or brief explanation appended to an article, illustration, cartoon, or poster.
A key is an explanatory list of symbols used in a map, table, etc.
Legend is more generic, while key is more specific. Neither word implicates anything about the location of the text/list.
A legend explains symbology and iconography on a map. For instance, a cross icon may symbolize the location of a church, or a heavy black line may represent a highway. A key on the other hand, conveys the meaning of thematic information. Thematic information would be something like an area being colored in a certain way to identify a statistical attribute (e.g. a choropleth map that shows California colored blue and Texas colored red to communicate political affiliation).