An offer is a proposal made by one party to another, expressing a willingness to enter into a contract on certain terms.

Capacity refers to the legal ability of a person to enter into a contract. It is not an essential element of a valid contract, as minors and individuals with mental disabilities may still be bound by contracts in certain circumstances.

Acceptance is the agreement to the terms of an offer, resulting in the formation of a contract.

Silence, in general, does not constitute acceptance. However, in certain circumstances, such as when there is a prior course of dealing between the parties, silence may be interpreted as acceptance.

Consideration is the thing of value exchanged in a contract. It can be anything of value, such as money, goods, services, or a promise.

Past consideration is not a valid form of consideration, as it has already been performed before the contract was entered into.

A bilateral contract is a contract in which both parties make promises to each other.

Void terms are not a valid type of contract term, as they are unenforceable by law.

Implied terms are contract terms that are implied by law or custom, even if they are not explicitly stated in the contract.

Terms implied by the court are not a valid type of implied term, as they are not based on law, custom, or usage of trade.

A variation of contract is a contract term that is added to a contract after it has been formed.

A written form is not a requirement for a valid variation of contract, unless the original contract was required to be in writing.

An unenforceable contract is a contract that is not legally binding due to a lack of consideration.

Undue influence is not a ground for rescission of a contract, as it is a type of duress.

A void contract is a contract that is void from the beginning due to illegality, incapacity, or lack of genuine consent.