An 'account' is a specific location for recording transactions of a like kind. For example, in the gas-for-cash transaction above, two accounts are used, a "Cash" account and a "Gas" account. Unused by that example, but described is an account for "Equipment" which would include the portable gas can and the lawn mower.
The basic types of accounts are:
'Assets:' items of value that the company owns or has right to. Examples include: cash, real estate, equipment, money or services that others owe you, and even intangible items such as patents and copyrights.
'Liabilities:' obligations that are owed to other parties. Examples include: wages payable, taxes due, and borrowed money (also called debt).
'Equity:' the ownership value of a company. Examples include: common stock and retained earnings (we'll describe retained earning below in "Financial Statements")
'Revenues:' the mechanisms where income enters the company (note that revenue and income are not the same thing--they are used here to describe each other in basic terms only).
'Expenses:' the costs of doing business. Examples include: salary expense, rent, utilities expense, and interest on borrowed money.
'Income:' in U.S. business and financial accounting, the term 'income' is also synonymous with revenue; however, many people use it as shorthand for net income, which is the amount of money that a company earns after covering all of its costs.