Answer:
They are both words, so it depends on when you use it.
Explanation:
con·duc·tion
/kənˈdəkSH(ə)n/
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noun
the process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or of electrical potential between adjoining regions, without movement of the material.
con·vec·tion
/kənˈvekSH(ə)n/
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noun
the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.
