Here is what the On Line Dictionary says about each
Hope this helps clear up the question
ranch (rnch)
n.
1. An extensive farm, especially in the western United States, on which large herds of cattle, sheep, or horses are raised.
2. A large farm on which a particular crop or kind of animal is raised: a mink ranch.
3. A house in which the owner of an extensive farm lives.
intr.v. ranched, ranch·ing, ranch·es
To manage or work on a ranch.
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farm (färm)
n.
1. A tract of land cultivated for the purpose of agricultural production.
2.
a. A tract of land devoted to the raising and breeding of domestic animals.
b. An area of water devoted to the raising, breeding, or production of a specific aquatic animal: a trout farm; an oyster farm.
3. An area of land devoted to the storage of a commodity or the emplacement of a group of devices: a tank farm; an antenna farm.
4. Baseball A minor-league club affiliated with a major-league club for the training of recruits and the maintenance of temporarily unneeded players.
5. Obsolete
a. The system of leasing out the rights of collecting and retaining taxes in a certain district.
b. A district so leased.