1. Cell theory states that:
All known living things are made up of cells.
The cell is structural & functional unit of all living things.
All cells come from pre-existing cells by division, (i.e. Spontaneous generation does not occur).
Cells contain hereditary information which is passed from cell to cell during cell division.
All cells are basically the same in chemical composition.
All energy Flow (metabolism & biochemistry) of life occurs within cells.
(biology-online.org)
2. The theory that cells form the fundamental structural and functional units of all living organisms; proposed in 1838 by Matthias Schleiden and by Theodor Schwann (www.thefreedictionary.com)
3. A scientific theory that describes the properties of cells, the basic unit of structure in every living thing. (Wikipedia.org)