What is a Logo?
Is it Symbol? A Combination Mark?
Does the distinctions matter?
The use or misuse of the word "logo" is one of those things that can frustrate a designer. A logo, they say, is not the same as a symbol, which in turn is not the same as a combination mark.
So what's the difference?
In brief: A logo is a word, a symbol is a picture, and a combination mark is a mix of the two.
But really, in most circumstances, using "logo" for everything is OK. Is it?
LOGOS VS. SYMBOLS
Although most people call any emblem that has been designed to visually represent a brand a logo, "logo" is taken to be short for "logotype," which is Greek for "word imprint". Only true logos are the ones that contain nothing but stylised letters, representing the literal name of a company. For example, the Coca-Cola emblem is technically a "logo".
Other logos include LEGO, Virgin and Ebay. Basically, if you see something in a company's emblem that can't be read, it's not strictly a logo. Or, at least, a logotype. But logotypes have issues in a global economy.
Because they depend upon being read, logotypes for English language companies (i.e. from the US and UK) might be confusing to people who live in countries that don't use the Latin alphabet. Sometimes, companies will modify their logotypes for different markets accordingly: Coca-Cola, for example, maintains a stylistically consistent logotype in many different alphabets. Coca-Cola's logo for China is one example.
In these modern times many companies prefer to take a more abstract approach, creating a universal symbol that abstractly represents their brand. The most successful in the world is Apple's iconic fruit. No words just a symbol. There is no translation needed for global recognition. The actual symbol represents Apple without the company name being present.
Other examples are Nike's "Swoosh", McDonalds "M" and the "Shell" oil logo. You know who these companies are without the need of using the name. The symbol is enough.
COMBINATION MARKS
Finally, there's the combination mark. These are emblems that use a combination of both words and symbols to represent a company or organisation. McDonald's, Domino's Pizza, Starbucks, The North Face: all these companies use combination marks. Some companies use both logotypes and symbols, depending on the context.
Nike, for example, has both a logotype and a symbol, which can be used to represent the company in different scenarios. The Nike swoosh by itself might work on the side of a sneaker, whereas a combination of the swoosh and the Nike logotype might look better on a company letterhead.
Adidas, however, uses a mix of different symbols with the logotype to create multiple combination marks yet retains it's brand identity.
DO THE DISTINCTIONS MATTER?
A symbol may not be the same thing as a logo, but abbreviating both logotypes and logo marks as "logos" is totally logical, because both types are meant to do the same thing. In fact, "symbols" are often referred to as "logos" for just this reason. The distinction between a symbol and a logo might be useful to designers, who may want to pin down what type of logo a client is looking for but 9 times out of 10, just saying "logo" is fine.
While "logo" is a perfectly fine "catch all" term, as designers it is still important to know the difference between a Logo, a Symbol and the Combination Mark.
For arguments sake.