In vitro (Latin for (with)in glass) means within a test tube, or just outside a living organism (a cell). An example is In Vitro Fertilization. The opposite of in vitro is in vivo, within a cell. As many experiments that deal with molecular biology are conducted outside of cells, and the conditions do not necessarily represent the conditions inside the cell, results are often annotated with in vivo or in vitro.
... from 45 to 64, and 13.5% who are 65 years of age or older. The median age is 40 years. For every 100 females there are 102.1 males. For every 100 females age 18 and ...