lacunae — a gap or missing part, as in a manuscript, series, or logical argument; hiatus.
parentheses — either or both of a pair of signs () used in writing to mark off an interjected explanatory or qualifying remark, to indicate separate groupings of symbols in mathematics and symbolic logic, etc.
seasons — an oratorio (1801) by Franz Joseph Haydn.
terms — a word or group of words designating something, especially in a particular field, as atom in physics, quietism in theology, adze in carpentry, or district leader in politics.