an abstract place usually conceived as having depth | the skilled practice of a practical occupation |
a subpopulation divided into a stratified sampling | the business given to a commercial establishment by its customers |
people having the same social, economic, or educational status | a particular instance of buying or selling |
one of several parallel layers of material arranged one on top of another (such as a layer of tissue or cells in an organism or a layer of sedimentary rock) | an equal exchange |
| the commercial exchange (buying and selling on domestic or international markets) of goods and services |
| people who perform a particular kind of skilled work |
| steady winds blowing from east to west above and below the equator |