An open sentence, also known as an open statement, can be defined as a statement that contains one or more variables or unknowns. Synonyms for an open sentence can vary depending on the context in which the term is used but generally include phrases such as "unresolved statement," "incomplete equation," or "unsettled proposition." These words all indicate the same concept as an open sentence, which is a statement lacking definitiveness and requiring additional information to provide a complete meaning. Other synonyms for an open sentence may include ambiguous statement, vague proposition, or undetermined statement, all of which describe a statement in which the meaning is yet to be defined.