Laughter refers to the sound of laughing, produced by air so expelled; any similar sound. It commonly describes a movement (usually involuntary) of the muscles of the laughing face, particularly of the lips, and of the whole body, with a peculiar expression of the eyes, indicating merriment, satisfaction or derision, and usually attended by a sonorous and interrupted expulsion of air from the lungs and a reason for merriment, which gives the term a broader and more practical sense than a single short definition would suggest. Taken together, these meanings present Laughter as a flexible theme rather than a narrowly technical label, covering the central idea people usually mean when they use the word while still leaving room for closely related senses that appear in real language. Laughter therefore works well as a quotation category because it can hold direct statements about the subject, figurative uses that borrow its meaning, and broader reflections that stay anchored to the same central idea. Laughter is not limited to a single rigid definition in ordinary language, and that wider range is part of what makes the category useful for grouping related material without losing the term's main sense. When used as a theme, Laughter can support serious, reflective, argumentative, or even playful quotations, provided the wording still connects back to the core idea described by the source definitions.
