A word, group of words, or a phrase used to conduct a search, generally through an online search engine like Google. Ad campaigns, websites and blog posts can be tailored around anticipated keywords to more highly target advertising, and optimize search results (SEO) for greater exposure and profitability.
Ex. work, home, work from home, and working from home, are all distinct keywords regardless of how many actual words are used in each. Plural and singular words, e.g. teddy bear, and teddy bears, require careful consideration as they might be treated as either synonymous or separate keywords based on context and user intent. This is where a tool like Google’s Keyword Planner (requires free Google AdWords account) becomes indispensable.
Keyphrase is sometimes used anonymously when a keyword contains more than one word, but this departs from general usage established by Google and others.
Contrast with long-tail keywords that are generally longer variants of a keyword that is more specific and generally less competitive, but which can sometimes yield greater advertising results if used properly.