Key Words/Key Phrases
Words or sets of words used to improve ranking in search engines when those words are phrases are entered by a user. For example, if a person does a search for "pet supplies", while a person who has the key word "pet" in his page, the page with the key phrase "pet supplies" will be ranked higher in the search results.

Knowledgebase
A Knowledge Base is an adaptable environment where organizations store data, content and help files. It provides the structure to organize and manage this knowledge, and present it in a user-friendly and searchable format.