What type of contract is described as one-sided where one party makes a promise?

A unilateral contract is defined as a one-sided agreement where only one party makes a promise or takes on an obligation that the other party can accept by performing a specific action. This type of contract typically involves an offer that invites performance rather than a promise in return. For example, if a person offers a reward for the return of a lost pet, they are making a unilateral promise: the person who finds and returns the pet is not required to do so but can choose to accept the offer through their action.

In contrast, a bilateral contract involves mutual promises between two parties, where each party is obligated to fulfill their part of the agreement. A conditional contract is dependent upon certain conditions being met, which is not reflective of the simplicity of a unilateral contract. Lastly, an implied contract arises from the actions or circumstances of the parties involved rather than from a direct agreement, highlighting a more nuanced understanding of obligations compared to the straightforward nature of a unilateral contract.