Answer:
palisade  - 3. wooden stakes set firmly and closely together in the ground. used for the defense of frontier forts.
joint-stock company  - 1. stockholders, any one of whom can sell some or all of his or  her shares without the consent of the others.
Piedmont  - 4. A plateau or district lying along or near the foot of a  mountain range.
Malaria  - 2. An infectious disease, caused by a parasite that is  transmitted by the bite of an infected mosquito, that causes  periods of chills, sweating, and fevers.
Tidewater  - 6. Low-lying land along a seacoast through which tides flow.
Quitrent - 5. A fixed rent paid in money, instead of services rendered
Explanation:
<u>Palisade</u>  - It is specifically a stake which is set on ground to provide a fence like structure that work as defense of frontier forts. 
<u>Joint-stock company</u>  - Joint-stock company has two or more partners with equal or different shares of company and stockholders can sell their stock without the consent of other partner.
<u>Piedmont
</u> - It is defined as a district or platue that is found near the foot of a mountain range.
<u>Malaria  </u>- it is an infectious disease spread due to bite of a female anopheles mosquito.
<u>Tidewater  </u>- It is the land area attached with seacoast through which tides flow.
<u>Quitrent</u> - It is a rent paid by a freeholder without hamepring the services.
Hence, the correct matches are:
palisade  - 3.
joint-stock company  - 1.
Piedmont  - 4.
Malaria  - 2. 
Tidewater  - 6. 
Quitrent - 5.