Esters are a type of organic compound. Often, they are the chemicals that give plants and foods their odors.

Common Esters

Another example of esters is fats. Fats are esters of glycerol (1,2,3-propanetriol, or glycerine).

An Example of a Fat
    H                O
    |                ||
 H--C--O--H    H--O--C--CH2CH2...CH3
    |
    |                O
    |                ||
 H--C--O--H +  H--O--C--CH2CH2...CH3
    |
    |                O
    |                ||
 H--C--O--H    H--O--C--CH2CH2...CH3
    |
    H
  glycerol    three misc. fatty acids

                  ||
                 \||/
                  \/

    H     O
    |     ||
 H--C--O--C--CH2CH2...CH3
    |
    |     O
    |     ||
 H--C--O--C--CH2CH2...CH3
    |
    |     O
    |     ||
 H--C--O--C--CH2CH2...CH3
    |
    H

     triester of glycerol (fat)

Credit to Avis Rapax because I didn't know about 2-methylpropyl ethanoate until I saw his writeup