In CycL, a formula, represented in the Cyc Knowledge Base by #$CycLFormula, is a type of term that consists of a CycL expression that denotes a relation (e.g. a predicate) — or at least an expression that could be interpreted as having a relation as its semantic value — followed by one or more CycL terms, with the entire sequence enclosed in parentheses. For example, (isa France IndependentCountry) and (GovernmentFn Spain) are both CycL formulas. Non-atomic terms and CycL sentences are both types of CycL formula.
An Euler diagram of terms in Cyc.