1 Simple molecules [molecule: A molecule is a collection of two or more atoms held together by chemical bonds. 2  It is the smallest part of a substance that displays the properties of the substance.
Eon has a number of meanings. In Astronomy, an eon refers to 1 billion (109) years. But it also refers to a very long, unspecified period of time, or specific geologic stages of the Earth.
end of day (EOD) Indicator often used to designate the time by which something must be completed. EOD traditionally is around 5:00 p.m., the end of the standard workday, but can vary depending on the time zone that the person or company is located in. Most often used in the abbreviated form when written, and in the longer form when spoken.