Equivocation

Equivocation is where a word is used to mean one thing at one point but another thing at another. An example would be: In the first sentence bank is a financial institution but in the second sentence bank is used to mean a geographical feature leading to the faulty conclusion that a person puts their money into the river.
 * The bank is where I put my money
 * A river has a bank
 * Therefore the river is where I put my money